Overall you have approx a 2.5' difference.
My thought would be somewhere you measured or read the tape incorrectly.
As for the pins that could be possible, I suppose a lot would depend on the overall weight for the actual pin placement on a trailer They all can't be say, 2' front the front of the nose cap.
One more thing, this kind of comes with that stupid question "did you plug it in?" By chance do you have a 5th wheel hitch with a slider?
When it comes to measuring "measure twice cut once"
Has to be a simple explanation.
07- Classic 2500 LT CC 4x4 SB Duramax/Ally
13-320RLT Crusader TE
Reese 16K Kwik Slide/Prodigy brake contoller