I am not convinced that this one weekend would "do it", because Shannon was fucking people left and right. Frank was only one of the many as far as we know. And really - I would fully expect Shannon using that during the trial to convince the judge to extort money from Frank because he has to support his biological daughter. In this case the judge would not go for that, because all the children where not his. I cannot imagine Shannon would NOT use that powerful hammer to destroy Frank financially. That she did not use that hammer is frankly (no pun intended) evidence she could not use it, because it was not the case in the first place.
Anyway - I would not like to see the possibility that Becca is Franks daughter game-play-wise. If we let the story rest for a moment and look at the game play for now. Until now the amount of whining from Frank is somewhat bearable...... Just....
Just imagine that would go up with a factor 100 if it turned out he was fucking his biological daughter. Can you see it?
If that's the case I would suggest to give the VN some choices at the start. Something like:
1.) Some whining (Easy Mode)
2.) High amount of whining (Normal Mode)
3.) Insane amount of whining (Hard Mode)
4.) Ridiculous amount of whining, combined with mental breakdown (Nightmare Mode a.k.a. Becca daughter mode).
Just kidding guys! Don't take this too serious.
But please give Frank a break. Things are difficult enough for him and he's finally accepting what is happening... Somewhat...
The judge said something to the effect of 'since the children are adults, child support is not an issue' As for child support possibly continuing after 18, while J.D. Google says there are some cases where that happens, none of the common ones apply in the situation. Becca is 23, has graduated college, and has a job. Furthermore, she (and Lilly) are paying rent to Shannon; a relationship that would be put at risk if Beccas parentage came out.
On a metatextual level, the Judges 'the children are adults, therefore no child support' was said so matter-of-factly that it is probably what CNG thinks, and it's not unreasonable that they wrote Shannons lines assuming that's what she thinks, regardless of the actual law in whatever jurisdiction Single Again takes place in.
As for the story, I don't think Frank will become aware of any issue with Beccas paternity until the events of her side story, by which point the whining will have been greatly diminished. As much as it gets brought up in this thread, Frank has been on a trajectory of whining less, even as he has become more sexual with the girls.