i agree 100% with this especially about how the flake is layed the the direction is very critical because it can reflect the light in a different way then the oem paint and make it look darker/lighter and posts like is is why if i owned a body shop would turn down panel painting or make sure they understand that there is a high chance of the color not matching, neals auto has been around a very long time and painted alot of show cars back in the day, from eddie habecks(spelling) Camry to adams cirraco (spelling haha) and alot of bikes as well hes not perfect so maybe he did fuck up but id give them the chance to fix it with the understanding that you brought him a bumper to paint without the car there
from the OP i believe he brought them the entire car. i completely understanding if it was not a match if he didn’t have the car but if he did there is no excuse