I think it has to do with fatigue. I heard Ainge talk about it. On Defense, there is no coasting. You have to be prepared for every play to come your way. On offence, say you are a wide receiver and a run play is called. Your only job is to trot down the field and pull a guy with you so that he would be so far away from the runner that he couldn't make the tackle. Some truth to that I think. And that's the whole flop thing. Let's give are guys a break, let them catch up to the offense and in the meantime, make adjustments, just like a timeout and even better, substitute in some fresh players. By golly, we don't even have to use a timeout even.
If you go back and look at the times flops occurred, the VOLS were ripping down the field like a hot knife through butter. After the flop, lucky to make a first down. It's effective against an offense like Heupel's.