St. Vincent HH Trem set screws

I’ve noticed my St. Vincent HH model has 2 different set screws on the trem. One on the rear of the bridge (Facing away from the headstock, you have to dive the bridge to see it), and one on bottom of the trem arm socket (facing out the back of the guitar).

I figure they have to do with trem arm tension, but what is the difference between these two screws?

Thanks!