Medicare premium hold harmless rule: Will the higher premiums paid by to medicare by those delaying SS benefits to age 70, revert back to the lower premiums enjoyed by those that have the premiums deducted from their SS deposits? Or will I always be locked into the higher rates?

Scotty,
The lower premiums for those held harmless are only temporary, until COLAs catch up to the premium increase, so eventually everybody winds up paying the same premium.
Best,
Mike