Tires: OE P to LT replacement, why not?, load tables, lb load

Question
After coming across this surprising information and then finding much more via internet search, I keep seeing the idea that when replacing P-metric tires with same size LTs, pressure needs to go up according to load inflation tables (Approx 10-15psi). I see here that you agree with this which is surprising to me as I had included your load tables page at Tire Tech among the body of contrary info I'd found,  Apparently, I misunderstood. Much of the contrary info I've collected is suppositional or indirect so I won't bother you with it, but here's a piece of straightforward evidence for your consideration:  FJ Cruisers come with P265/70/17 OE tires. The TRD edition, which is not meaningfully different for this discussion, comes with 265/75/16 in LT load D. The door sticker pressure for the former is 32psi, for the latter, 35psi. I can't find the load inflation tables for this particular LT brand but I've seen the tables for other brands and the numbers are nearly identical between brands. So, making that assumption, it looks like these OE FJ LTs are at about a 600 lb load disadvantage (approx 1900 compared to 2500lbs) per tire at the door sticker pressures. Seems very odd for Toyota to do this if the P to LT idea is widely agreed upon. Before I was hit with cold water via a couple of your answers on allexperts, I was coming to the conclusion that the explanation to all this was that LTs were engineered to tougher standards with a higher margin of safety that was reflected in more conservative limits published as numbers in load inflation tables but without the contextual back story. In other words, the overall vehicle/tire safety would remain about the same for the P to LT switch, without more pressure, if vehicle usage remained the same.  

Sure hoping to get a satisfying answer to this. Thanks.

Answer
Jeff,

I did a little digging and I can NOT confirm that the TRD edition comes with LT's.  According to all the sources I looked at, it comes with P265/75R16's - whereas all those sources also indicate that the other versions come with P265/70R17's.  Both of these tires have very close to the same load carrying capacity.