By the time you have reached your max weight, you have already spent energy on 50% and 75%. That energy you could have put towards your 100% weight. Do a couple sets of light warm up (15-20%). Then do your 100% weight. If you can do more than 10 reps for your first set, increase the weight on your next workout. Do 2 sets of your 100% weight, and take each set to positive failure.