good tax return software

I have done our tax return with the tax program WISO the past 4 years. The tax return is done within 2 hours, and very simple.
Unfortunately, there is not every year back as much money as the program always calculated. Why is that, I have not yet figured out. But it is always an average of about 1/4 less than calculated by the program.
The operation of the software is very easy thanks to the wizard.

PS: It takes time to write reviews on Amazon. It would be nice if I get some feedback. Many Thanks!