Overlord - Cheat/Bug

This is a bug I found in Overlord at the smelting room. As you can see in the video I only sacrificed 50, but you can sacrifice up to 100 and not lose any minions. Why is 100 the maximum? I don&know. If you sacrifice more than 100 a random amount of minions will be lost. All you have to do is choose what you want to upgrade, then tell it to sacrifice up to 100 minions. Then exit right before any minions jump into the smelter.