How many chains do you need?

Chain recommendations for the bench press:  

Under 200lbs bench - 20-30lbs

200-400lbs bench - 40-50lbs

400-500lbs bench - 80-90lbs

500+ bench 80+lbs

Chain recommendations for the squat:

Under 200lbs squat -  40-50lbs

200-400lbs squat -  50-60lbs

400-500lbs squat -  60-70lbs

500-600lbs squat -  80-90lbs

600-700+lbs squat -  90-100lbs

800+ squat 120-140lbs