It's pretty obvious from the posts on this thread that there are many opinions regarding the original question. From reading lots of other threads and some tire manufacturer's web pages, it seems to me that the basic need to balance the tire/axle/trailer weights and capacities is being overlooked. Specifically, I believe it is recommended by trailer manufacturers and axle manufacturers that you never run tires that have a higher load rating than the axles as it will put too much stress on the axles.
So, adjusting the load rating downward to reduce the load capacity of the tires by reducing air pressure may take the stress off of the axles, but it will most likely result in a reduced wear life for the tires.
IMHO the retailer didn't do you a favor by mounting the LRE tires as they are not "better" tires, they are just "stronger" tires and they are not within the weight parameters for your trailer.
Lew TAC #WI-6
Nobody can help everybody, but everybody can help somebody.