Really? I thought the sweet spot was 50-60 minutes. As for your question, I don't usually see any penalty hits from minutes ranging from 48-60. Most of the time, if they drop, they are random GS drops that cannot be controlled. When I get my players at 65+ minutes, their GS usually drops by 1 or stays the same. In rare occasions, some people do pop in GS after playing 70-80 minutes, but not often. Hope this answered your question!