RANGE FINDER QUESTION

I was playing around with my new range finder and got some odd readings. I was ranging my back stop where I have got targets setup and got different readings . On the light silver color metal it read 34 yards with is what it actually is. On the brown rusted metal it read 35 yards, on the black rubber matting that is attached to the metal backing it read 37 yards. All three materials are 34 yards. Does color of object make a difference when measuring? Is this normal or is my range finder defective?
 
"mr.grimm"It gives the same results . I am new to using a range finder this is my first. So I was not sure if these readings were normal.. I was not aware that you could get different readings depending on target color at the same range.
I've got a cheap range finder. It says XRT on the cover. It acted like that when the batteries were dying. It has never varied much because of the kind of surface I was ranging. You should make sure your batteries are new and go to the local golf course (if they will let you) or a foot ball field or base ball field or some such that has known ranges and distances and check your range finder out. If it is accurate to a percent or two you are golden.