German body comp

I was wondering in the german body comp workout, it says reps of 15-20. should I choose a weight where I can do 15-20 RM, or a weight where i could probably 20-25 RM and just stop at 15-20 reps? any help would be great. thanks.

When I do the program (To great personal success) I do the first exercises in the 10-12 range, then 12-15, occasionally above 15 reps, but that is a rarity. I go to failure on the sets. I wouldn’t do it the way you speculate. The weights would just be to low.