i looked up the crossing thing. found nothing for that in texas 545.410 that says you have to cross the chains or cables, if these haven't changed anyway. hop, i do agree, crossing the chains is good, but i didn't see it was law. it looks like you were snookered on the chains but it does appear the towing speed limits have changed
texas
elaw

(2) The two safety chains will be of equal length, long enough to permit free turning of the vehicles without placing stress on the chains, and attached to the towing vehicle equidistant right and left of the point at which the vehicles are connected. The safety chains must be connected to the towed and towing vehicles and to the tow-bar in a manner which prevents the tow-bar from dropping to the ground in the event it fails or becomes disconnected. In no event will the safety chains be allowed to contact the road surface during movement of the vehicles.

I'll offer this : In the summer time in TX, with the hotter road temps, I tend to trailer slower than I would in winter with cool roads. I'm normally between 65-75 (possibly more if passing), except heat of summer, then I normally don't go over 70. It may not make that big of a difference until that one time you have a tread peeling blowout that crushes the diamond plate fender down to the hub and wraps the tread around the axle on the side of the highway in 100+ temps with the sun bearing down!