Spring recall / Sagging rear end but not equal

I have in coil spacers on the front of my truck. The in coils spacers were there when i bought the truck. The truck was pretty much leveled out. My truck may have been slightly higher in the front. I went to my local dealership on the leaf spring recall. they replaced the springs. Now my truck is lower in the rear end. today I actually measured the rear end from the center of the hubs to the fender. they are different left to right.
19-3/4" on the drivers side and 21-1/2" on the passenger side

Ive been reading about adding a leaf spring or blocks or what ever to make my truck level again. but whats the deal with the difference in height left to right?