Grand Junction · Medigap or Advantage for 2027

Should I Switch From Medigap to Medicare Advantage for 2027?

Every October a few of our Plan G clients in Grand Junction lay a Medigap renewal notice next to a $0 Medicare Advantage mailer and ask whether they are overpaying. For 2027 the Mesa County shelf is 10 Advantage drug plans, 8 of them $0, with in-network caps from $4,900 to $9,850. Switching is easy. Switching back is the part the mailer leaves out, and it is governed by a 12-month federal trial right and, after that, by a Colorado health application. Here is the whole trade, both directions.

Medicare On Main Data Desk

Published October 1, 2026 · 9 min read · Reviewed by Brian Penner, 22+ years in Medicare

Mesa County is unusual for a Western Slope county: more than half of its Medicare population is still on Original Medicare. The CMS monthly enrollment file for June 2026 shows 41,709 people on Medicare here, 22,554 of them, about 54%, in Original Medicare and 19,155 in a Medicare Advantage plan. 15,944 people buy a stand-alone drug plan, which is the signature of someone with Original Medicare and, usually, a Medigap policy. So the question in the title is being asked by a lot of households this month, and the answer depends less on which plan is "better" than on whether you understand that the door only swings freely one way.

The trade, line by line

Here is what changes when you leave a Medigap policy for a Medicare Advantage plan, with the 2027 Mesa County figures from the CMS landscape file where a figure exists. Our post on the 2027 Grand Junction plans lists every plan by name with its premium, cap and drug deductible.

Sources: CMS CY2027 landscape file, Mesa County MA-PD rows; Medicare.gov Medicare costs; Medicare.gov Medigap benefit chart. Part D deductibles on the 2027 Mesa County plans run $300 to $700.

Why the premium comparison flatters the switch

The mailer compares your Medigap premium to $0. That is a real difference, and over a healthy year it is the whole story. But the two products are priced on opposite ends of the year. A Medigap policy charges you up front and then, under Plan G, leaves you with the $283 Part B deductible and nothing else for Medicare-covered care, no matter how bad the year. An Advantage plan charges you as you go, in copays and coinsurance, up to the in-network cap. For 2027 that cap in Mesa County is $4,900 on the two tightest plans and $9,850 on the loosest, and a PPO's out-of-network cap can be higher still. Original Medicare on its own has "no yearly limit on what you pay out-of-pocket"; that is what the Medigap policy fixes, and it is what you are giving back.

So the arithmetic is: the Medigap premium you save, times the years you hold the Advantage plan, against the cap you are exposed to in the years something goes wrong. A hip, a cardiac stent, a cancer diagnosis, a $1,736 Part A deductible that Plan G would have paid. For a household that can absorb a $4,900 year without noticing, the switch can pencil. For a household that would feel it, the Medigap premium is the price of not having to.

Two things do not change when you switch, and people sometimes think they do. Your IRMAA surcharge is identical on either side; it attaches to Part B and Part D, not to the plan. And the drug benefit is the same federal design, with the 2027 out-of-pocket cap, whether it comes bundled in an Advantage plan or as a stand-alone plan next to your Medigap policy.

What you give up that is not on the mailer

• Any doctor who takes Medicare. Medigap has no network. The question for an Advantage plan is whether St. Mary's, Community Hospital, your primary care doctor and the specialist you see twice a year are in the 2027 network, and we have a post on checking that before you enroll, not after.
• Out-of-state specialty care without a referral fight. Grand Junction households use Huntsman in Salt Lake, the Denver systems and Mayo in Arizona. On Original Medicare those are a phone call. On an HMO they are a referral, and on a PPO they are an out-of-network bill. That post walks through each case.
• No prior authorization beyond Medicare's own. Advantage plans may require it for the services they list. Federal rules now give you a 90-day transition when you change plans mid-treatment, which we covered here, but the day-to-day rules are the plan's.
• The policy itself. Medicare.gov's switch-drop tool says it plainly: "If you drop your Medigap policy, you might not be able to get it or any policy back later."

The one-way door, and the 12-month exception

Leaving Medigap for Advantage requires nothing from you but a signature. Coming back requires either a guaranteed-issue right or a health application, and Colorado offers fewer guaranteed routes than some neighbors. There is no birthday rule here, no annual window where a Medigap company must take you regardless of health. Outside your original six-month Medigap open enrollment, Medicare.gov's own tool says your options "may be limited and the policy may cost more."

The exception is written into 42 U.S.C. § 1395ss(s)(3)(B). Clause (v) covers the person who "was enrolled under a medicare supplemental policy," then "subsequently terminates such enrollment and enrolls, for the first time," in a Medicare Advantage plan, and whose Advantage enrollment "is terminated by the enrollee during any period within the first 12 months of such enrollment." Clause (vi) is the other trial right, for someone who joined Advantage at 65 and leaves within 12 months. If you fit (v), Medicare.gov's tool says you "can buy the Medigap policy you had before you joined the Medicare Advantage Plan, if the same insurance company you had before still sells it," and if it does not, "Medigap Plan A, B, C, D, F, G, K, or L that's sold by an insurance company in your state." You apply "60 days before the date your Medicare Advantage Plan coverage ends" and "no more than 63 days after."

Read the two conditions again, because they are the whole post. For the first time. If you tried Advantage years ago, went back to Medigap, and are thinking of trying again, there is no second trial. Within the first 12 months. Not 12 months from the day you decide you are unhappy; 12 months from the day the Advantage plan started. A January 1, 2027 start means the Advantage coverage has to end by December 31, 2027, and the usual way to do that is the Medicare Advantage Open Enrollment Period, which Medicare.gov describes as "January 1-March 31," "only if you're already in a Medicare Advantage Plan," or the next AEP for a January 1, 2028 return. Miss it by a month and the guarantee is gone.

You cannot keep the Medigap policy as a safety net

Some people ask whether they can keep paying the Medigap premium for a year while they try the Advantage plan, just in case. You can keep paying. It will not do anything. Medicare.gov's switch-drop page: "Your Medigap policy can't pay any Medicare Advantage Plan deductibles, copayments, coinsurance, or premiums, if you decide to keep your Medigap policy." The illegal-practices page goes further: "If you enroll in a Medicare Advantage Plan, you'll be disenrolled from Original Medicare and can't buy a Medigap policy," and it is illegal for anyone to sell you one while "You're in a Medicare Advantage Plan, unless you're switching back to Original Medicare." The trial right is the safety net. It is free, it is federal, and it lasts 12 months. Paying a second premium for the same protection is money out the window.

Who the switch tends to fit, and who it does not

It tends to fit a household that is healthy today, has a doctor and hospital already in the plan's network, takes prescriptions that sit on the formulary at a reasonable tier, does not travel for specialty care, and could write a check for the cap without changing anything else. It tends to fit less well as the health picture gets more complicated. Per CDC PLACES, 26.6% of Mesa County adults live with high blood pressure, 29.8% with obesity and 8.1% with diabetes, and those are the conditions that turn into the specialist visits, imaging and hospital days where copays add up toward the cap.

It fits worst for the person who is switching to save the premium and has a procedure already on the calendar. That person pays the Advantage copays on the procedure in year one, and if the experience sends them back to Medigap the trial right covers them, but a year of copays is often more than the premium they saved. If a known event is coming, the cleaner move is usually to keep the Medigap policy through it and revisit next October.

What I would do

Price the policy you have. Call your Medigap company and ask what the 2027 premium will be, and whether a lower-cost plan letter, or high-deductible Plan G with its $2,950 deductible, is available to you. In Colorado that is its own health application unless you are inside a guaranteed-issue window, so ask before you assume. Sometimes the premium problem is solved inside Medigap and the Advantage question goes away.

If it does not go away, do the three checks on the specific 2027 plan: network, formulary, and where you would go for anything serious. Then decide with the trial right in mind. Write the end date of the 12 months on the calendar the day you enroll. Make the Advantage decision by December 7 so it starts January 1, and if by the following fall you want your Medigap policy back, you will still have time to use the one guarantee federal law gives you. We help with this every October from our Grand Junction office or by phone anywhere on the Western Slope.

How we know all this: the Medicare On Main Data Desk frames every article with public data — here, the CMS CY 2027 Medicare Advantage and Part D landscape file (data last updated September 22, 2026) for the Mesa County plan count, premiums, in-network maximum out-of-pocket amounts and Part D deductibles; the CMS Medicare Monthly Enrollment file for Mesa County, June 2026; 42 U.S.C. § 1395ss as published on Cornell LII for the trial rights; Medicare.gov's guaranteed-issue tool, illegal-practices page, switch-drop tool, joining-a-plan page and Medicare costs page; and CDC PLACES for Mesa County health prevalence. No 2027 Star Rating is stated because CMS has not published them. Medicare On Main is a licensed independent insurance agency. We do not offer every plan available in your area. Any information we provide is limited to the plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. Not connected with or endorsed by the U.S. government or the federal Medicare program. Plan names appear as published in the CMS file; nothing here is a judgment of any company or plan.