It is computed from the revenue entries you make, so check them. Also check the instructions for what goes in this line.

I haven't seen Lacerte get it wrong.

1.   Make sure you were comparing it to the Current Year and not Prior Year.

2.  If it's still off, check if Page 1 line 12 (Current year, again) matches to Part VIII Col A Line 12.  If not check how the numbers in your input flowed to the respective lines.

3. If there is still an error, call Lacerte support.  Without seeing your data, it's hard to pinpoint on the problem.