People just training wrong. More volume, more time under tension, lower weight. Average around 60% of max. When you can do 80% of your max for a 20 RM you are a body building god.
Instead of hitting the highest weight once, you should be hitting as many reps for as high as possible weight. People don't seem to understand this. 5 reps is strength & mass, 6 reps is negative gains, 8 is body building, 15 is endurance, and 20 is cardio to these fucks. If you can do 20 reps at 80% of your max (once again) you are a god.
Orbit around 60% of your max, going up to 80% or down to 40%. Focus on volume progressions. Add weight each macro cycle not in the micro cycle. An even better measure for these volume progressions is using a percentage of a rep max, such as 12 reps of your 20 RM for 6 sets. Increase sets/reps, decrease rest. You can throw in a heavy single for a couple sets and your workout the next day won't suffer (90% x 1 rep x 2).