Yes, its proportionate. You can even level weapon skills for weapons you don't have equipped, so long as they are on the active skill bar.

Want to level resto staff and some of its skills, but don't want to gimp your solo killing speed, just stick the one you want to level on your active dps bar

as a VR2 I have one castbar right now that I use as main for fighting in pve. and a second castbar with 5 unfinished leveled skills, when I turn in a quest I switch to that castbar and gets them leveled up.

that way ill have lots of skills to choose from

almost all 3 armor, cloth, light, heavy are at lvl 50 as well, heavy is I kept 1 of each the whole time I was leveling just to get them all up

In my second cast bar, I have another weapon as well, that way ill level that up as well beside my main weapon

almost got 4 different weapon kind at lvl 40 one of them closing in at lvl 50