Actually, I stole the numbers from others, but it's pretty basic.
2011 regular season price is $46
A cs breakfast is about $8-$10. Cs lunch/dinner is $14-17
And most snacks are $2-4.
So at regular season 2011 prices, about $3 for snack, $14 for cs, and $29 for ts. Anything above, is "savings."
2011 peak pricing would be about $31 for ts.
2012 regular season ts is about $32.
2012 peak season is about $34.
Yup.
Faldred came up with the initial calculations. I applied them to the 2012 plan to see what we came out with. There's quite a bit of math behind them, but it seems to make sense and works out nicely.
They're actually based around an average $3 snack and it uses the pricing of the QSDP to figure out the QS credit cost, and then subtracts all that funky stuff to figure out the TS cost. 2012 is a bit easier, since we can just call the mugs as free since all levels receive them now (it used to make a slight difference for Dx and QS as they were added value).
-- Wandering Mind Warning! --
In the thread about upping the poster's child's age to 10 so they could apply credits for themselves at CRT found a neat little thing about CRT dinner. It may actually be the exception to the "don't use TS credits for 2 credit meals" rule IF you have at least 1 kid for every 2 adults AND you are doing dinner. (And this is only off of 2011 prices)
CRT dinner is ~$55 for Adult and ~$34 Child or 2 TS credits. So, just for the adults, you're going to be ~$5 behind on each. However, using a slightly different method for kids meals (which also seems to get decent, plausible numbers) of $3 snack, $3 CS, $6 TS (so it's $12 - snack = meals then 2/3 meals = TS, 1/3 = CS), this shows a rough gain of about $11 per kid. So with 2 Adults and 1 kid, it's basically a wash. For increasing the ratio of kids to adults, you will actually save money on
DDP here, reversing it and you won't.
Of course, this only works for dinner as the adult prices are too "low" at breakfast and lunch to make up with the vast difference in the kids' pricing. And it only works for 2011, as I didn't bother looking at 2012 prices

.
And, of course, it's still better money-wise to pay OOP for adults here and use DDP credits at more expensive per-credit meals, but for those who are more prone to try and keep everything paid for by the same method, it's not really a big hit to the overall savings. (And, this little math thing only works with parties where the Adult to Kid ratio is at the very least 2:1).