I had a situation that came up today in a JV game in Texas (no 10 second subtraction due to High School exception)
3rd and 10 with :51 seconds to go in the half, team A is leading 20-0. The game clock is running when team A commits a false start. They were rushing out of the huddle to snap the ball and not all players got set, so I shut it down and correctly penalized them for false start.
This, to me was a gray area. If I start it on the ready, it penalizes team B by eating up the time. If I start it on the snap it benefits team A by giving them extra time.
So, I just resumed the clock to what it was doing prior to the foul.