The calculations in TurboTax assume that the return is for a full year, and you may not be able to override the amounts it calculates.

We have another program called Profile, which is made for accounts, so you can override almost everything. Please aware that the program is Windows only and only has forms (no interview mode). Also it uses EFILE, not NETFILE, but you will likely have to paper-file anyway, if you make a lot of overrides to the calculations. You can buy profile here: https://profile.intuit.ca/profile-onepay/