“CMS defines a Late Penalty as an amount added to your monthly premium for Part B or a Medicare drug plan (Part D) if you don’t join when you’re first eligible. You pay this higher amount as long as you have Medicare. There are some exceptions.” – www.medicare.gov

“…is a lifelong surcharge added to your monthly premiums for Parts B and/or Part D if you don’t enroll when you’re first eligible. (Exception: can be avoided if leaving an employer group plan after you become age 65.)”