Okay... I have an 81" vanity, with one side up against the wall. It is made up of two 30" sink cabinets with a 21" drawer cabinet in between.

My vanity top overhangs the right side by 1". The left side is against the wall with a backsplash. The sinks are centered in the 30" cabs.

I have a 15" cabinet on top of the vanity (like appliance garage). It is 12" deep. My contractor did not center it between the sinks. He did not center it over the 21" drawer cab below. He measured the center of the vanity (which is lobsided due to the overhang on one side and the wall on the other) and centered it on that. He said that would give my mirrors (30w x 36h) equal reveal. Keep in mind my mirrors are not special... they are just clip-to-the-wall mirrors.

The result is that it is off by a half inch. From the side of the cab to the right sink, it's 7.25". From the side of the cab to the left sink, it is slightly over 8". I could tell the minute I walked into the room. The cabinet is set, the outlet inside is in, the backsplashes are on and the caulk is caulked.

Am I an idiot for caring or is he for measure it this way? What is the standard way to set such a center cabinet?