Are you using a 3 man crew for 11 man? That would be tough. Here in Oklahoma we call some 8 man with a 3 man crew, using an Umpire, WH and HL. Lots of running, but everything seems to work out well. I could not imagine doing an 11 man game with just 3 officials.
We only use a 3 man crew on Jr. High games, Most schools are now paying for 4 officials for J.H. games.