I had mine done recently. Passenger side already had deep scratches when I went to pick it up. Showed the CSR and he made notes for a second visit to replace it and he apologized. After paying more close attention to drivers side it also had deep scratches. The passenger side was poorly...
I would guess that having accessory 'on' powers up a DC to AC inverter which inherently has loss. I do believe sentry mode does activate the camera heaters in cooler weather so that could add to the drain. I noticed when snow covered the areas around the pillar cameras are clear of snow.
For...
I live near Toronto and we use a lot of salt on the road. Driver side is okay, but passenger side is awful. I have to use a lot of washer fluid just to get it what you see in the picture.