@dmk741 Yes, but the total load is only going toward your legs/hips/butt. You only press 1KB with your shoulder. Your shoulders/arms/grip would take an 8kg DECREASE per side (16kg total load) to gain 4kg INCREASE for your legs.
@dmk741 You’ve already outgrown double 12s. Your legs are not going to be the weak link here. And your arms can already do 20kg. Get a matching 20, or an adjustable.