That explained a lot, I never thought to apply the Store TP value to the additional hits. Although that brings up more questions..
This model skips 19 TP return, which I have quite often. If you applied the Store TP values before rounding down to 13.7 (13.72) then it would skip 18, which I also have very often, most actually. But it does make sense, I'll just have to pay more attention now that I know and see my results. Although I just added more Store TP with Ravager's Lorica +2, so the progression should be 17 > 18 > 20 > 21 > 22. So if I see any 19 TP returns I'll come bother you again.