Simply repeating the question down in the "Message" section that you already asked up in the "Subject" box isn't much of a help when it comes to a reader trying to understand what you're asking about. What deduction are you talking about here? It appears that you're talking about depreciation, though that's not clear. If you enter you information into TurboTax properly it does calculate depreciation. And what's "the 2.5%" you're referring to? A rental house - which may or may not be what you're talking about here - has a higher depreciation rate then that.
