Question about long-length partials in The Pure Bodybuilding program

Hello everyone,

In the program The Pure Bodybuilding program, I am supposed to do long-length partials. I get what that is, but I don't understand how to get the intended RPE. Let's say I am doing Straight-Bar Lat Prayer for 3 sets with 12-15 reps. In the first set I get 15 reps and in the second set 14 reps at RPE 9-10 (as prescribed). Then in the last set I am doing long-length partials for RPE 10. But as I am only doing "half reps" I probably end up doing more reps than 15 to hit RPE 10. So the question is: do I add more load to stay in the right rep range, do I just max out the reps at the same weight used in set 1 and 2, or do I do something else like slowing down the movement?

Also a follow up question: are you generally supposed to change the load between sets to hit the right number of reps and RPE?