wait, which kit are you basing your figures on?

https://www.amazon.com/Litorange-Standoff-Threaded-Motherboard-Assortment/dp/B07D7828LC/

this 320pcs kit has 20 pieces of the 20mm + 6mm standoff.

https://www.amazon.com/Augiimor-Female-Standoff-Motherboard-Hexagonal/dp/B08FBRNVWP

this is 50pcs for $6.

Or am I looking at the wrong kits/standoffs?

I was hoping to buy off of someone who already has such a kit and has spares.