If you go into forms view you can override most numbers, but some forms have other rules that could cause your override to be viewed as an error. Just know what you're doing. I'm not a tax professional, but I've had to do this several times after going and reading the IRS literature to figure out the nuances of the rules and how the calculations should be figured. I haven't personally found it computing taxes incorrectly except when improperly handling certain worksheets that input into the taxes - in which case the problem is in the worksheet calculation and not the tax calculation.