I know exactly what you mean. If you are already fast at those percentages you are ending up working too much in the speed-strength realm. It's going to depend on individual movements sometimes but I can end up spending more energy on decellerating the damn thing at too low a percentage, as well as losing touch with the bar, as you are saying. May as well be doing medicine ball or smith machine throws..which is a whole nother topic.

If you've ever done medicine ball throws you'll realize that you don't start really relating to the ball until you've gotten very fatigued and it becomes a perceived effort kind of thing. Now, that could help explain the feeling of more benefit from RE work, maybe.

But I think it is an individual thing to some extent and and training status to some extent like you mentioned so what it comes down to is what I always say "what happens is what matters".

For me I tend to get more benefit cycling through from 55 to around 65 percent for a number of weeks and then testing, or backing back down or whatever. Not for all lifts, of course. But again, I believe, and have personally derived the most benefit from the "intention is what matters the most" way of thinking. But I KNOW that some people are different.