This whole discussion that seems to be focused on specifications rather than actual real time performance reminds me of how that whole focus can get very perverted and misapplied:
There is a story supposedly where our USA NASA needed a writing instrument in the space capsule that would work in zero gravity. Supposedly over $1 million of our tax dollars were spent on writing a procurement specification and development contract to get a ball point pen designed that would work at zero gravity and not leak. They succeeded at getting such a device designed and built at quite a cost to us taxpayers. Ever wonder how Russia solved that problem?
They used a lead pencil.
I must repeat myself. LT tires on heavy trailers have proven they have a much lower reported failure rate than equivalent ST tires. That is good enough for me and therefore I have installed LT tires on my 5th wheel after having 2 sets of ST Tires fail. No further tire problems. Were LT tires specifically designed for Trailers and 5th wheels? Probably not but they work better and are more reliable than the ST tires. So do we really care what the specs are? Yes, we would all like to know why they are better but at this moment in time we are lost in debating the specifications and are not able to see the forest for the trees.
The bottom line is: They do the job reliably. Do we need to know more?