Weird return value discrepancies between Softshell and RTL-SDR

I've made significant progress porting over the rtl-sdr code. I added printfs to every function that interfaces with the USB port so that I can compare what happens. Everything seems normal, up until the gainControl function. Once there, the returns from my application are usually about one digit off of the rtl-sdr code. If anyone has any ideas, I'd love to hear them!

Link to the comparison spreadsheet.