What you are talking about may be A problem, but it is not THE problem being discussed in this string. This string is talking about how TT is applying a limit on the repayment amount of the APTC for folks that have a MAGI of over 400% of the FPL when the repayment amount is not, in fact, limited. TT seems to have acknowledged this problem, with someone reporting a fix expected in early February.
If you MAGI is over 400% of the FPL, per the form 8962 instructions, you enter 401 on line 5 so there is no issue here with any possible sort of incorrect rounding.
If you do think there is another problem (which would only happen if your MAGI is less than 400%), then you should start a new string on it and not highjack this discussion with it.
