Passenger Trains > Metra roof colors

I see Metra 199 has a black roof with the latest paint scheme when most/all of the similar model repainted units on the BNSF line have the silver/gray colored roof following their updated paint jobs. Was the black roof an experiment/mistake/modification to the new scheme? I believe some of the other model units in the newer colors on other Metra routes also have black roofs but I think only the 199 has it on the BNSF route at this time.

I suspect it is a nod to the challenges of keeping the white/gray clean. My understanding is that all future repaints will use the black roof.