@Khobai Well, the way I see it is this:
"During the Command Phase, a unit can be issued an order only once, even if a game effect causes that order to be removed or issued to another unit instead ."
directly ties into this:
Authoritative: "When you would be issued an order, you may issue an order to a friendly unit at range 1-2 instead. "
Emphasis mine. To me, it looks like Authoritative directly ties into the rules of not being able to be given another command when you've issued your order to another unit instead. As other posters have noted, I doubt this would allow the tank to double up on aims since it doesn't count as a trooper for her 2 Pip, and she never had possession of the order she is passing along.