NS Black Paint

I work for a large transit authority in the Southeastern US, the name of which I cannot reveal for myriad reasons. We are currently changing our bus paint scheme from a white overall base coat to a black overall base coat/majority color. Not knowing the specifics, I am privy to information that says we are mixing various colors of Dupont paint the blue toner of which costs $331.79 per QUART (!!!) to achieve our desired shade of gloss black.

Before I make a suggestion of where to go to save money on what I'm almost certain is a wasteful process that our paint vendor is conning us in to, I need more data:

Does NS custom mix it's black locomotive paint on site as we are currently doing or do they buy it in bulk pre-mixed in gallon cans or 55 gallon drums? If so, who is that vendor and what is the unit cost they charge agencies like mine.

It seems like the paint they are using is quite durable as NS locomotives rarely look scratched-up and/or faded and don't seem to show blemishes readily. I feel certain there are plenty of folks on this forum who can provide the info I'm searching for, so let me say in advance that I very much appreciate and profusely thank anyone who can help me/us out.

I don't have the answer you're probing for... but I gotta wonder why you'd paint commercial transit vehicles from white to black, especially beneath the hot sun of the Southeast. Better have good air conditioning in them things.

FWIW just give a look at Keeler & Long epoxy coatings. They have the positive reputation to be allowed in Nuke plants, so I'd assume it's probably some top notch primer and epoxy. Some of my nuclear projects specifically demand the use of Keeler and Long. Otherwise, sorry if its not much help.

Hindsight thought; perhaps NS black is a takeoff or derivative of military spec paint. That could be a really tough nut to crack.