There is no point in climbing to 20k, and if you do you will find yourself diving down to 13k at least to get a kill. This is one part that makes this game unique, gotta conserve and watch out for your ammo and gas,, that unlimited crap is for am amateurs... It is a part with being generally new to this game.. it is very difficult. That is why you gotta be aggressive and not be afraid to go to the DA to fight or to ask people to help with ACM because in this game it is important.
+1