Anita,
I've done project judging several times at Regionals and States. I am not an expert, but just a normal, average, coach/judge. At most tournaments there is about 5 minutes allotted for students to present, about 5 minutes for judges to ask questions, and a couple of minutes to get everyone in and out the door. Different judge teams do things differently. Sometimes they will warn with 1 minute left. Sometimes they will let the team know they have been presenting 5 minutes.
We have tried to let the kids finish, so if it is a few seconds, it shouldn't be a problem. But, realize that judges are trying to ask teams similar questions, and if they can't ask your team the questions, they don't have information to compare. For example, if the judges ask about sharing, and one team has done a lot of sharing and talks about it, then your team also has also done a lot of sharing, but doesn't get a chance to answer the questions, it is possibly a comparative disadvantage to your team.
There are no points involved. After every presentation, the judges are asked to rank the teams compared to all previous teams they have seen that day.
I have coached and judged for 4 years. I strongly encourage all coaches to judge at least once. It really helps to understand the FLL program, and it is a very enjoyable day of volunteer service.
Amy Trombo
co-coach BrickBeasts