Reverse Engineering

I don't intend to discuss about reverse engineering on the classic and academic way. I prefer to talk about it's usage in automotive industry.
At a glance, the main goal of reverse engineering is exact copy of reference part or assembly but it is not all things. My experience says in some cases even after exact copy, especially in assembling parts which each part has movement to others, final product doesn’t satisfy normal function. For example, in Peugeot 405 HVAC Actuator, we could see some disordering in our product function.
If you open this actuator you can see a plastic gear box with an electronic board (PCB).
Here, I have a picture from HVAC Actuator which designed in CATIA. I put it here for shining subject.As you see, two little red metal brushes which exist on the big cream gear, and move on the green PCB. In fact these two brushes adjust shaft start and stop position (park position).
In the next picture you can see PCB. It is clear that the profile on the PCB is very important to getting good park position. After designing and produce, I found out that our product didn’t normal function. CMM report didn't show any important things.
So, where was the main problem?
What was there we didn't see that?
At next post I will draw a new part in CATIA step by step.