Its not probaly, its sure try it yourself if you can handle to loose some milions:
You put your prices
You click ok=>its sold as soon you press ok
As you said, the new koxp can make some things, but it seems this guy gets some access to the database cause a macro is a "auto do it", it cant do what you can do with your hands a infinite time (wallhack, and speedhack is different, they modify shits client side).
You cant click on a long away merchant to see the price = a normal macro is not suposed to do it neither.