Thanks for the clarification - I have a very bad feeling that a lot of tournaments are not following this rule. I see way too many tournaments advertising "added cash" and then the numbers don't add up. Take a look at the 2013 Texas States NT. They advertised $10,000 added cash but unless the greens fees were $6,000 (they only played this tournament on one course) then something looks fishy there.
I don't know what the specifics were for the 2013 TSC but talking with some of the TD's in the north Texas area there are some cities that make running a tournament at their courses very costly. For example McKinney charges $2.50/person for an event (last time I heard from the city), while one of the neighboring cities wanted almost 25% of all money taken in by the tournament. Round Rock might have charged much more than anyone would think in order to reserve the course and comply with city regulations involving sporting events.
I also forget sometimes to look at the added cash to payout in all the pro divisions and not just the MPO and FPO. A lot of the B tiers add $500 but its portioned out to masters and grandmasters as well. I know that the TSC had a fairly large masters and grandmasters field that would have to get some share of the money.