Split Colour - Back and Front of Cabinets Different Colours - Yes !

We recently were asked if splitting colours on backs and fronts of doors
is possible and why you might want to consider this...

With darker colours -like a burgundy on the front sides, a higher light
 reflectance colour like an off-white helps you see better into the lower
cabinet areas...and if doing black on the fronts (speaker cabinets etc.)
it makes sense to have a light grey on the back side. Does it add to
cost ? Only for the additional colour as we spray individual sides, allow
cure then flip for the next coat, so there is no real extra labour....