Generally, most sensible Q&A participation should be completed by the time the projects are due. However, sometimes students still have legitimate questions to discuss after the presentation (e.g. "I saw X group did Y -- how did they do that?").
I probably won't tally up final points until later in finals week, but if students are asking silly questions or posting silly answers just to grub for points, I may very well delete those and/or penalize their scores.
Serious questions and thoughtful answers about software development and/or programming are always welcome!