Tires: LT to P, why not?, inflation pressure, rare exceptions

Question
I understand the argument for not replacing P-metric tires with LTs, but why would the reverse be true? Barring unusual circumstances like using a P in really harsh conditions, the load inflation tables indicate Ps have much more load capacity at inflation levels most people will or would prefer to run them (low 30s). In other words, Ps seem to be much safer. So why not go from LT to P? The fact that they're de-rated when used on SUVs would seem, if anything, to only bolster this argument. They still spec much better than LTs at the same pressure after the de-rating.

Answer
Jeff,

I think you will find - with very rare exceptions - that the inflation pressure specified for LT tires is much higher than the normal 35 psi maximum you find specified for P metric tires.  Given this, there are virtually no opportunities for a switch of this type to take place.

Besides, it is quite common for folks to ignore the letters that accompany the number in the tire's size.  Even Tire Rack omits the letters and it has caused problems.  So I want to emphasize that there are some differences and sometimes they are important.