Confusion over Medicare's penalty for late enrollment means many older Minnesotans got the wrong information.

Thousands of older Minnesotans who miss the May 15 deadline to enroll in the new Medicare drug benefit probably will pay a slightly higher penalty than they had been told. 

The culprit is bum information from the state of Minnesota, the Minnesota Senior Federation and some national advocacy groups that incorrectly explained the penalty. 

They apparently got it wrong because of mistakes in materials Medicare used to train counselors around the country, said Kelli Jo Greiner, a Medicare expert with the Minnesota Board on Aging. 

She has trained hundreds of counselors with the Minnesota LinkAge Line -- 1-800-333-2433 -- which helps more than 3,500 Minnesotans a week make choices about the benefit. 

Many beneficiaries were mistakenly told that if they wait until January to enroll, their penalty will be 1 percent for each month of delay, calculated against this year's national average monthly premium of $32.20. That would have resulted in a permanent penalty of $2.25 a month on top of their drug plan premiums. 

In fact, the penalty will be based on next year's average monthly premium -- an amount that won't be known until fall, when Medicare approves the 2007 drug plans. And the penalty will rise each year if the national average premium rises as expected. 

For next year, the difference between what late-enrolling beneficiaries expected and what they are penalized may be modest -- an additional 70 cents a month, if the average premium goes up $10. But over 15 or 20 years, the rising penalty will add up. 

A spokesman for the Centers for Medicare and Medicaid Services confirmed how the penalty will be calculated, but could not point to a government website that spells it out. 

"We didn't need this," said Janine Stiles, a Medicare expert with the Minnesota Senior Federation. "People already are overwhelmed by the complexity of Part D without having to deal with errors."