brake piston?

I have a 1996 cutlass iv been having brake problems squeaking etc maybe the rotors are warped i'm not sure.



and i just wanted to know if the dual piston on the front are they suppose to come out and disengage simultaneously...I took off the wheel and put a piece of wood in the caliper where the pads usually are and had some one press on the brakes.......on driver and passenger side one piston comes out before the other the one closer to the brake line on the caliper comes out first and the other is about half way out...when the brake is applied constantly it eventually catches up with the other piston..........Is this normal function? is it the master cylinder since both sides do this? Thanks

Normal, when the pistons see equal resistance from the brake pads things even out.

i know it was sorta a silly question but hey i didn't know thanks