FYI the retro pay hit isn't as bad the closer the end of the month you finish. I finished around the 26th or so and the pay hit was negligible. Now your checks will be less of course because there will be no per diem yet too. Say you finish 7/31, your 8/31 paycheck will have no per diem as it is paid out the end of the following month (Aug per diem paid on 9/30). Confused yet?
Btw same with OT, it's paid out the end of the following month.