XRAY - Model racing cars

I have done a search dont think I have found what I was looking for. I have a raycer and I have had a problem with checking ride height from where it is specified. when checking from the front under the bumper and from the rear I see that there is like a 1 to 2 mm dif then when I measure from the eadges where it seems to be at the "right" ride height. I am almost possitive that the chassis is tweeked to hell but I have had the same problem with new raycer chassis. is the side of the chassis the place to measure from or is there something I am missing? Also is this a problem with the CF chassis? I am sure it isnt. help me. thanks.

The composite chassie on my car is not flat try a straight edge across the car it looks to me like its designed this way it flares up on the sides which would account for the differance in measurement.