Mhh ... at least here in Germany I have this experiences:
Black powdering with structure, full armor set is around 150 EURO.
This guys are working with big industrial parts, farmers, etc, pp
They can work with the common german RAL colors. No problem.
BUT ... a coindoor with candy powder , this is the wrong address.
F. eks. with candy powder there is a need for a first coating with "Chrome", over that chrome comes the powder color, f.eks. Copper.
On the coindoor the hinge is a beast ... you cant "just powder" it, otherwise it will break if you open the door the first time.
I am sure in this cases ... candy and doors, it might be better to have someone specialised in candypowder and/or pinball stuff.
So, I have one guy for legs, etc, pp in black with slight structure. Around 150 Euro.
A specialist making wheels, motorcycle parts and pinballparts in candy asks 250 to 400 for a whole set. Specially the benamed Copper powder needs chromepowder as a first layer, so that is double the time to work and double material.
Therefor I would not blame the "experts", but sure ... some people see the pinballscene as a fat cow ready for milking.
Just a brief look in the advertisments here on pinside and you understand what I mean ...