Given that the work record "Clean and Jerk" for men is 263.5 kg (about 585 pounds) and for women it is 182 kg (about 405 lbs) you math would imply that no human has ST 20. I was under the impression that olympic weightlifters regularly got to ST 20+, which would imply the qualifying weight you've set it too high.
Weightlifting world records
I calculate the male record as ST = 22,
excluding any Lifting skill or extra effort, so that's a reasonable maximum if we assume you can "clean" 6 x BL.
The women's record implies ST = 18, same scenario.