Arm speed/strengthening throwing program

This winter on top of the tuffcuff workouts, My pitching coach is getting me to do an arm speed program with lighter balls to increase velocity. Basically what were doing so far is before every practice 3 sets of:
5 throw with 2-3 oz ball
5 throws with 3-4 oz ball
and 5 throws with regulation ball
all throws 100% about 60 feet away, against a wall
the idea is that we have to work harder to get out, and on top of the heavier balls, forcing us to speed up our arms ahd throw harder.
Has anyone else done a similar program?
realistically, doing this and the tuffcuff workouts and nutrition, how much can i add on to my fastball which tops out aroud 80 mph right now? I am 15 years old 6’ 160 lbs
thanks for all input!