I could be wrong, I have been before.....but I was under the impression you can only write off up to the amount that you were paid in perdiem. For instance if you were paid 5000 in TAFB. then you can write off up to 5000 ............not 20,500 on 5000 worth of TAFB.
but who knows.....
His per diem probably was 20,500. I know how much he flies and it is all long layovers.