Probably wanna be at 115lbs for 5~6 reps to be sure but it also highly depends on the individual. Some people are a lot better at more reps and some are better at lower rep heavier sets. Me for instance, when I hit 355lbs on bench, I could barely do 3 sets of 2 with 315lbs. Now at 380lbs that looks more like 2 sets of 5 with 315lbs.