Thanks very much for your answer, but I'm still confused.
I downloaded the pdf you referenced and used the table A-6 and still get a number over 16k, not 12k. It appears from this table that the math does indeed work that way. Further, last fall I paid a CPA to look at my taxes to make sure I was doing them correctly, and according to him, the only thing I'd been doing wrong was using too small a depreciation value (turbotax had been giving me the 12k figure for years).
Any further thoughts? (Thanks again)
