Troubleshooting

I understand that..  I assumed CWB as that was the amount difference between the calculation.  I am using TurboTax online so, it is not a desktop issue.  I am trying to find out the issue.. Is it Turbo Tax if so, do they guarantee the difference when it is the mistake of TurboTax.  I had done my mothers and my girlfriends with no issues in their calculations.  So, it is not the software either.