EX FSO ASA doesn't charge for a touch and go, only the fullstop landing. The touch and go fee is purely a JAH thing. Having worked there until recently I can assure you we don't stick to 12 for the fun of it. It's a nightmare as most people are unfamiliar with is and we really need to keep a close eye on everyone.
But your right, YMUL is closer and cheaper unless you have a reason to be in YBUN.