If someone DC the Killer will auto gain a stack on his Perks
It's very annoying when someone disconnects and you can't get the stacks from this person. So why simply automatically add the stacks to the Killer's perks if he runs appropriate perks like BBQ, Devour Hope, Play with your food, etc.
If the Killer runs 4 perks that can be stacked, well then he gets 1 stack on each perk. Don't punish the Killer for a DC.