Perhaps 20 wins in WCC = 8 wins in the former MWC. However, there will likely be multiple tournament teams from power conferences who get an at-large without 20 wins. The conference matters a lot, and BYU's independent football schedule is much more difficult than its basketball schedule. 

There is a possibility that BYU may not even get invited to the NIT, which is essentially like being left out of a bowl game. I would translate that to about a 6-win football season.