Additionally, any signing bonus is coming from BMD's passing the hat and is facilitated by people who know how to do fancy paperwork. It's not like it's money being taken from the mouths of students on scholarship.
ETA: And $10 million a year sounds unreasonable, but $8 doesn't? I mean, if Bama is paying $7.2, Texas would have to have been offering at least that in order for them to renegotiate the extension. It's not unreasonable to assume TX would be willing to pay $8, not with an NC on the brain, so... yeah. And this isn't an argument in defense of TX getting Saban, just an argument in defense of the lengths BMD's are willing to go to put their alma mater back on top.