Q: AppleCare using lower quality retina displays when repairing?

so last month, my mid-2012 retina display starting showing signs of banding. i was out of warranty, so i paid apple to fix the problem and they replaced the retina display. after bringing it home, i noticed that the colors weren't as vibrant as they were before, so i compared it to my sister's retina model (same exact model and build), and my assumptions were correct. the colors weren't as vibrant, and blacks seemed lighter; it seems as if the backlight was turned way up.

i reinstalled os x in case any default color settings were changed and played with the advanced calibration settings, but i can't get it to match the display on my sister's computer. the problem is definitely with the hardware.

i tried my best to take a picture of the two side by side to show you guys. both computers are plugged in running on full brightness with the exact same color settings. the display on the right is my sister's. it has deeper and richer colors, and you can more easily make out the details of the surface of the planet. the display on the left is the one apple just replaced, and it seems a little whitewashed with much poorer contrast.

i have 90 days after the work was completed to bring it back to the apple store in case there are any issues. is this something i can have fixed/replaced, or will they just tell me something along the lines of "tough luck, we can only replace it with the parts we have on hand"?

i'm sorry if this seems like a small detail i'm griping about, but i paid around $2000 originally and hundreds more to have the screen replaced, so i'd at least expect the same quality.