Counselors who help seniors consider Medicare insurance options say they have found a troubling number of inaccuracies on a federal government website for making health plan choices.

Since open enrollment began in October, counselors said they have seen a number of errors with the premiums reported for various health plans on the Medicare.gov website, including instances when all options were listed as charging no premium when that is true only for a subset of health plans, according to officials with the Metropolitan Area Agency on Aging, a nonprofit group based in North St. Paul.

While problems with premium prices haven't been surfacing as often in recent weeks, counselors said they are still finding errors with information displayed about consumers' out-of-pocket medication costs.

"We believe that it is quite serious," said Dawn Simonson, executive director of the Metropolitan Area Agency on Aging, which operates a help line for seniors. "We'd like to see an extension of open enrollment once the [website] tool is fixed, in order to give people an opportunity to perhaps disenroll from the plan they've selected and enroll in a plan that is the best fit for them based on accurate information."

The Centers for Medicare and Medicaid Services (CMS), the federal agency that runs the website, said it investigates every year reports of issues with benefit information displayed on Medicare.gov. This year, the "Medicare Plan Finder" tool was updated for the first time in a decade, CMS said, and outfitted with new resources to help consumers make decisions.

"Extensive consumer testing throughout the development of the new Medicare Plan Finder was [performed] to ensure that the information that is displayed is complete, streamlined, understandable and is in plain language," the agency said in a statement to the Star Tribune. "Drug pricing and availability is constantly changing. ... CMS investigates each case individually to ensure that plan formularies are current and accurate on Medicare Plan Finder."

Rebecca Johnson, a spokeswoman with Bloomington-based HealthPartners, said the insurance company was aware of a few glitches with the website, but hadn't seen an effect overall. Representatives from Blue Cross and Blue Shield of Minnesota, Medica and UCare — three other health insurers that cover a large number of Medicare beneficiaries in Minnesota — said they weren't aware of problems.

But the Minnesota Association of Area Agencies on Aging issued a statement this month saying its members are "deeply concerned about pricing inaccuracies and other issues."

In some cases, the federal website has been showing wrong information about drug formularies, which are lists of medications covered by particular health plans, said Kelli Jo Greiner, senior policy analyst at the Minnesota Board on Aging, which is a state agency. In other cases, the information about premiums and out-of-pocket costs doesn't match data the state agency receives directly from insurers, Greiner said.

"There have been fixes to some problems we saw when open enrollment first started, but there still are outstanding issues that have not been fixed yet," she said. "Our concern is that even though CMS is working on changes, all the changes haven't been done yet and we're concerned that people are making decisions and enrolling in plans that aren't going to be the best for them in 2020."

Insurance counselors said the problems aren't so bad that seniors should stop using the Medicare Plan Finder. The website is unique in showing plan options from multiple insurance companies while also helping estimate out-of-pocket costs with different coverage options.

But consumers should be careful, state officials said, to double-check information with insurance companies before making a final decision on coverage.

"It's best to call the plan and confirm that the information is accurate," Greiner said. "The majority of the people we're assisting, we're finding the information in the tool is not 100 percent accurate."

In some cases, counselors have searched options for consumers and found the Medicare website wrongly lists a zero premium for all health plan options, or the same premium for all products, said Rebekah Galde, a specialist who works for the Metropolitan Area Agency on Aging. Counselors help consumers dig for the right answer in those cases, she said, since they know from experience that the premium results are wrong.

The concern is that consumers using the website on their own might not know to seek better information, said Galde.

Problems with drug formularies are troubling, counselors say, considering the high cost of many medications.

"The errors that we're seeing there are about drugs that may be on the formulary, but the plan finder tool indicates they're not on the formulary," said Simonson of the Metropolitan Area Agency on Aging. "Or, of greater concern, the formulary indicates that they're included, and then when we check with the plan, indeed they are not included. That could be very costly for someone if the plan then didn't go forward with an exception."