When does Kill Command start doing more damage then Arcane Shot?
I am BM and always have been BM so my signature attack (apart from Intimidation...) should be Kill Command.
Arcane Shot however, a shot that costs a lot less Focus, does way more damage then my Kill Command.
I am now level 62 and the difference in damage from Kill Command and Arcane Shot is only getting bigger...
You really don't need to be concerned about ability damage as you're leveling. Like I said, the coefficients get all wonky. It probably starts to fix itself sometime in the 70's but I don't really know because it's not something people have done any research into.
Seriously don't worry about it until you hit max level. If anything you should like that AS hits harder at low levels, since it's more spammable.
At lower levels it doesn't matter, I'd say KC start hitting harder at 80 when you'll start getting Mastery as a stat. Apart from that, use AS if it hits harder, and throw in a KC if you happen to have threat issues (which would be rare, but unleashing too much AS on a mob before the pet can even reach it could do that easily)