Excellent explanation @RogerD1 !
I really appreciate your willingness to dig into my specific case to help figure out what was going on.
For sure the fact that the numbers ended up being so close ($1976 vs $1978) and the fact that the labeling is so similar (both being addbacks for tax deductions permitted at the federal level but not at the state level, but computed differently against different ceilings) only added to my confusion.
It seems my state has managed to thoroughly confuse me (and some others as well, judging by the posts).
Thanks again for all the efforts and best regards
k2michelin
