It's a common misunderstanding that when you use the sales tax tables you can add the tax on "major purchases" to the amount from the tables. TurboTax contributes to this misunderstanding by using the term "major purchases." What you are allowed to add is the tax on "specified items." The specified items are a motor vehicle, an aircraft, a boat, a home, or a substantial addition to or major renovation of a home. (This is a very simplified list. See the IRS instructions for Schedule A for details and limitations.)
Painting your house is not a substantial addition or major renovation, so you cannot add the sales tax for that.
There is a restriction that you can only add the sales tax on a home or a substantial addition or major renovation if the tax rate is "the same as the general sales tax rate." But in your situation it doesn't matter, because you can't add the sales tax for painting anyway.
