The Dissomaster online version that is released to the public does not calculate SS. Some counties no longer use SupportTax. Mine doesn't at all. I think at the last conference, only a handful are NOT exclusively using Dissomaster.
In any case, this was a short term marriage. The OP has already been told he isn't going to be paying SS for long and really, I think a lot of bench officers pull SS amounts out of their behinds.