BYU's tuition subsidy is on par with a moderately priced state school with a lot of out of state student athletes.
For most state schools the athletic department cuts a check to the school for the number of scholarship athletes times the in state tuition.
The tuition subsidy is the difference between in state/out of state tuition times the number of out of state scholarship athletes.
Either BYU has WAAAAAAAAAY more non-LDS athletes than I appreciate who are being paid for at the LDS tuition rate, or the AD simply isn't reimbursing the school for any scholarships.
Given BYU's low tuition, that still wouldn't cover the subsidy, so there's probably some actual direct payment to the AD occurring.