It will take a week or two but you'll adapt to the higher reps. I went from doing sets of 5 to sets of 15 and it took a week or two to adapt. Of course by that time I had moved on to sets of 10, but still But at any rate, I would bet that when you get into it after a few workouts, doing 140 x 20 will be easier than when you did 100 x 20 (hopefully).
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<BombScare> i beat the internet
<BombScare> the end guy is hard.