Help ordering zip dee for 16' Bambi

Anyone order an awning from Zip dee for a late model Bambi? I have a 2007 16' Bambi. I will order direct. They want the measurement from center rivet to center rivet at the bottom of the coach, following the top rail down along the main seam. This turns out to be the seam along the door and the one in the back behind the wheel.



Zip dee says this number should be 6' 8-1/4". But I'm measuring about 6' 9-1/2".



Help! :)