Yo man,
Though I agree with what Rob said, you might make better strength gains if you upped the reps. Improving on a 4-5 RM requires a pretty huge gain. I know you train strict and all, but you could probably eek out extra reps more consistently if you were working in the 8-12 range.
Great advice.....the top powerlifters cycle their training and don`t usually go for a max except in a meet.
Try high reps for a bit .....keep the resistance progressive,but never at the expense of form....a bit of body English is fine at times on certain things, but you have to decide if you want to be a bodybuilder or a powerlifter.
If you can only bench 200 pounds but look like you can bench 405....you`re good to go.
Make the reps hard....high reps doesn`t mean to use pussy poundages.......squeeze them out until the pain is insane,then do a few more.....fuck it....it`s only pain.
If you`re shooting for 8 reps....you should be dying on repn # 6.....same with 12 reps or whatever....HOMOESTASIS BRO....you have to make the body change cuz it doesn`t want to.