How To Measure The Windshield Frame For Glass

I have seen on here that the measurement for 1955-1975 windshield is 15.5" x 59" with the 76-83 glass is 15.5' x 55". I just bought a frame for my '55 CJ5 rebuild. I bought the 1968-1975 frame with the wiper mounts at the bottom. I am 6'2" and the glass for the '55 sat too low due to the wipers being mounted above the windshield glass.

Anyway, I measured the new frame 2 different ways (outside and inside like a picture frame). These are the dimensions I get -- 15 3/8" x 56 1/2" AND 16 3/4" x 57 1/2". Neither of these seem to match what I read on the internet. What am I doing wrong. The guy selling glass told me the dimensions for the glass were 15.5" x 55" which made me think its the later version.

Appreciate the feedback.

 

They did mine for $200. Plus tax

 

My glass was $91 at a local shop for a 3A frame.