Sounds to me that you guys have been going to dodgy powder coating companys. Ive been doing powder coating for over 6 years. The reason its better,yes thats right its better is due to the paint being chip resistant. It sounds to me that they are using the wrong type of powder,as you can't apply any old powder to something that flex alot. Secondly its most likely the chemical balance when treated is incorrect or they never treated the items in the first place, which will cause flaking and chipping easily. Powder is the industrial standard. If it was that rubbish then they wouldn't use it on buildings,even car body paint and wheels.

Hope that helps