This is a topic that you touch on in any of your resources that discuss RPE. I understand that it takes practice and being honest with yourself. However let me give you a real example and ask a couple more in depth questions. Maybe this is something others have experienced:
I am going through the Bridge for a 2nd time.
I use RPE but also try to get close using your chart and my estimated 1RM. In my most recent lift I was doing squat 5@ 6, 7, 8. On my second set, I was doing 315 for what i thought was RPE 7 or 8.
Since I wasn’t sure, and had been wondering about if my intensities were off, I decided to do a max set at 315 and see what happens. much to my surprise i did 9@9.5. So obviously I have probably been a little low with my intensities at times, but also I feel like my performance is varying. Is there a better way for me to do a sanity check from time to time to see if I am in the ball park?