I did the math, and mine matches protomech, with one huge unknown when calculating the 2012 savings. There are no 2012 model year numbers in the FYI yet.
If you look at the "incremental price difference" for the cars in the FYI, for most cars this price changes every year. The IPD for the 2012 can change, so exact math can't be done until those numbers are put in the FYI. But that brings up a huge question. Since the credit is no longer based upon MSRP, but on price paid, will they even put IPD's in the document anymore? The IPD's aren't even relevant now in 2012, because the actual price paid is what matters.
That of course opens up a whole bunch of new questions. Like, if you pay over MSRP, but get a free helmet, a free set of leathers, and a free extended warranty, etc in the deal, what price do you use to calculate the tax credit? It would seem by this FYI that your rebate would be based off of whatever number is on the receipt.