Infraction: 6. Do not post unless you have something new and worthwhile to say.
Message to User:
Posts consisting solely of "thanks" are better sent via PM.
OK, people, let's start learning to read the thread...
The Steady Shot should never fire under any circumstances because the macro statements are processed in order. This means that the Arcane Shot will always consume the CGD regardless of whether you are holding the <alt> key down or not, because that statement appears before the Steady Shot. If the Arcane Shot is on cooldown, you will still consume the GCD.
Try changing this line
/cast Arcane Shot
/use [mod:alt] Steady Shot; Arcane Shot
Two more things: explicitly ranking spells like that means that your macro won't use the highest version should Blizzard create one, even if you train for it. You don't need either of the '/cast !Auto Shot'. If you really want to begin your auto shots right as you press the button than put one in before any other shot.
This worked like a charm. Thanks!