TurboTax usually uses the mathematical method of depreciation, rather than using the "tables".
The order of the math is a bit questionable, but many other software brands do the same thing, so I don't know if it is actually wrong or not. It very well might be right.
If you don't like the way it is calculating it and if are using the CD/downloaded version, you can go into the "Forms" and into the "Asset Entry Wks". Scroll WAY down to the very bottom and check the box to use the "tables".
