Snoopy, I moved your post to its own thread, because it doesn't really pertain to the one you posted in.
HiLo measured its trailer length from the hitch point on the tongue, to the rear of the rear bumper (excluding the spare tire if one was mounted there). This means my 17 ft HiLo has a "box", the part you live in that's about 14 ft long.
I believe other trailer manufacturers consider the length of the box to be the trailer length (excluding the tongue and the rear bumper).
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew