I did a tax returns with TSJ indicator and in ProSeries MFS Vs MFJ Worksheet. I showed the TP (wife) who who showed Spouse (husband) and they will save $400 if they file MFJ. So yeah, MFJ saves a little tax.  However, the husband turned around and got his MFS filed with another tax preparer.  I had not met him. His preparer helped him filed MFS, not allocating  their combined community income!  Separate issue.