First thing is to know what kind of accuracy your shutter and your meter are giving. Without that, every exposure is presumed inaccurate. Especially the leaf shutters. I haven't found one accurate yet. You need to keep on top of them every minute. On the other hand I have a Nikkormat FT2 that has never been touched for service, and it's dead on the money. Yes that includes Hasselblad. They are way off, too. Without service, you can't say what is "1 stop overexposure". Knowing that and your meter accuracy, 1/3 over on color neg film is optimal.