Brilliant silver rear bumper a different shade?

bmarcinczyk14

So I'm gonna take it into the stealership tomorrow and present the bumper issue. How should I go about being as persuasive as possible to convince them to re-spary her booty? Should I tell them the paint seems to be discoloring or just say straight up Nissan did a shitty job color matching the bumper? I guess what it will really come down to is how bad they feel the issue is, and then try to convince corporate to cover the re-spray under warranty.

EDIT: Also something to note, I did not purchase the car from this dealer, I recently purchased Buick GMC dealer further away from me, but since the vehicle is still under warranty it shouldn't matter whether I bought it from them or not, correct?