I have been receiving social security benefits since 2014. During 2015 my Medicare Part B premium was $104.90/mo. This rate was maintained during 2016, but then SSA changed it later in the year whereby I ended up paying the standard rate of $121.80/mo for all of 2016.
Even thought I did not exceed the income threshold, had Medicare premiums taken from my social security benefit each month since Dec 2014, and of course did not receive a COLA in 2016, I was not protected from an increase.
Apparently, due to additional work and part-time earnings from 2014 that got applied at my full retirement age (66) for Dec 2015 and which carried over for 2016 (actually a gross increase in benefits of about $40.00/mo.), I was not protected from a Medicare Part B premium increase for 2016.
So my question is even though there was no COLA in 2016, and my social security benefits increased slightly due to work history, is it not appropriate to apply the hold-harmless provision rules in this case?
I don't have enough information about your case to be certain, but if you received an adjustment that raised your Social Security benefit rate by roughly $40 effective with the December 2015 payment (i.e. the payment issued in January 2016), then Social Security was probably correct to have raised your Part B premiums to the regular rate for 2016. Even in the case of a retroactive adjustment to your Social Security benefit rate, your Part B premium rate can also be adjusted retroactively (https://secure.ssa.gov/apps10/poms.nsf/lnx/0601001004).