Your numbers aren't quite accurate. According to HoopsHype the Spurs have a total of $41,831,628 committed in salary for next season. Tim is making 10 not 13, Tony is making 12 not 15. Since I've seen numbers (can't find the reference) that next's years cap will be right at 69 million, the Spurs are in pretty good shape.
As far as the speculation goes for salaries, Manu's not going to get 8 million and Tiago's not going to get 10 (at least not from the Spurs) http://hoopshype.com/salaries/san_antonio.htm