actually the taller you are the SMALLER your measurements will be, look at lee priest
hope that helps 
Not very smart are you MemberX
On the contrary if you are taller your arms will tend to look smaller due to longer limbs. But in reality they are large in measurements compared to someone shorter.
Do you really believe if you were 5 ft9 you would have 18inch arms? Looking from the pictures it looks like you have 15 inch arms but due to your height the measurements are going to be obviously larger.
Also the Lee Priest is a horrible example and further proves my point, Lee Priest had the best arm development in the business but they looked small compared to Levrone's, Flex or any of the top taller guys.