Just goes to show that size can be meaningless. I wear 25.5 inch back too (in some jackets) and I am 6 ft 2 (a foot taller) And it falls slightly longer on me than in your photo. Go figure...It also depends of your body shape.
For example, I'm 5'2 and usually need a 25.5" back length.
My Aero Sheene with this back length.