When you say obvious are we talking end of game to let the clock roll out?
If intentional, the clock would start on the snap.  Especially under the 2 minute regulation clock.   

You should be able to snap the ball on offense once the ready for play is set.  Now with mighty might some teams are more organized than others so there is some give and take there, especially since teams have to be set up on offense and defense a certain way.  If you have video you would like for me to review I can but unfortunately, it is not going to be an exact number every play with 1st and 2nd graders.