The one time SID at USU tells me that programs are supposed to report actual attendance, per the NCAA.

This is because schools have to average 15k in attendance over a rolling two-year period to avoid probation the possible loss of Div 1-A status. However, there was a rule change in 2005, it appears, that allows you to either average 15k in actual attendance over two years or have 15k in PAID (not actual) attendance once every two years. It is possible that the reporting of attendance changed with the rule change, I suppose.