Deductions & credits

I ran into that same issue.  I naively thought that the rule was back 6 months from when my Medicare would become effective, NOT  the date I started the application.  (I wanted to give myself plenty of time to see the application guidelines  -- so wanting to be prepared is a mistake.)  I can't think of any reason at all why the 6 months has to start from the date of application, when the desired  effective date is also on the application.   I am missing  something?