I think I might have messed up the fact that that they get the .008% returns each night. so i would in theory have to update the calculation to multiply the gains by number of days in the reverse repo. (is this 31? how do weekends work? if they borrow on friday, is it due monday? )

lets try the calculation with 31 days per month.

16,000,000,000(16 billion) * 31 = 496,000,000,000 (496 billion).

496 billion - 140 billion (th 7% inflation rate) = 356 billion in profit just from utilizing the reverse repo rate at .008 % after accounting for inflation. This actually means that they are making money on the reverse repo due to it compounding daily basically. Am I off here?