I see a lot of people at the gym doing flat bench (barbell) way to fast not to mention most of them bounce the bar off their chest. No wonder a month later they are still doing the same weight. Its not about the weight but about the form. Shit when i do dumbell curls my last set is usually 55 or 60lbs each. Now i do it slow and concentrate. I do 8 reps and my arms continue to grow. BUT somedays i will do one arm concentration curls on the percher bench with 35 or 40s and get twice the pump. Reason being is that the muscle is more isolated and the excerise is executed slower and with more focus. What i'm getting at is first drop the weight on your bench, and do it slow down and a bit fast up. Make the bar touch your chest and hold for a sec then push up. You 'll see the results.