I would say that being a coder or knowing mushcode does not make you able to modify ajobs. Ajobs is a beast of a thing that doesn't like to be messed with. Even if you do know mushcode and are a veteran coder to boot, Ajobs will chew you up and spit you out. That's how annoying it is. Really, the only people that know Ajobs are those poor souls who for whatever reason bring that soul crushing hell upon themselves willingly and work through the code.
I cut my teeth when I first began coding "seriously" (as seriously as I do anything mu*wise), on features for aJobs.