I have the procomp 2.5" and it gave ~3" initially and has settled somewhat, but still not to 2.5". Carrying a load in the back can get the AAL to settle faster if you don't like the height it gives you.
The average height of an add a leaf is around 3-5" sticking out of the top of the trash can, unless you put it in a dumpster. Then, it usually shows about a 3 ft drop. Either way, it's perfect after you perform either one of these two mods!!!