So i've been levelling via recruit a friend and I remember having done it a long time ago but are levels shared among an entire account or the individual character? I also read somewhere that there was a maximum of 39 levels but not sure if that's been changed or not. So far i've levelled one character to 80 which I would think is 40 levels and another toon to 26 which is another 13. My monk is currently 27 so would I be able to go from 27 to 80 just like that?
The levels are bound to the character who gained them and can only be granted to other characters on the OTHER account that are lower level than the granting character.
Blizzard has a nice FAQ about Recuit-a-friend that explains ALL of this.
from what i know for every 2 lvls you can give 1 lvl for free. but you can't lvl him abive your own. so atm you can only use your lvl 80 for the extra levels. and also remember that if you are lvl 40 and 99% till 41. and grand him lvls till 80 you will end up at lvl 80 with 99% alrdy done. so get to the highest % for that lvl and then start granding lvls