could be that you are not getting enough work time out of your muscles. By all means, go up in weight, but do not sacrifice higher weights for lower reps, thus less work. I've seen people working out that go high in weights, but throw them up so fast for so many reps and feel so proud of themselves, that very little work through the full range of motion was accomplished. The heavier weights should be progressively attained. your lack of "feel" may be due to a lack of overall intensity.