That math ($40M) doesn't make sense. That would mean that those 6 Pac12 teams would add $340M dollars to the Big12's existing deal of $380M.
If that was the case some of those schools would already be in the Big10 or SEC.
Even if there is some "incremental" benefit above the Big12's current $31.7M per school for adding those 6 Pac12 schools, when it gets distributed over 18 teams, the max increase would only be a couple million per school.
And why would the Big12 want to "reopen" it's ESPN/Fox extension? No guarantee ESPN or Fox would match what's already on the table.
I'm pretty sure ESPN has already accounted for any Big12 expansion with it's pro-rata close.
And FOX doesn't have a pro-rata with Big 12, so for Big 12 to expand Yormark is going to need to get Fox to pony up more money OR Yormark is going to need to get Amazon, Apple, etc to fill FOX's void.