Read a thread on an RV Forum on connecting two tires in dual position, with hoses to "balance" the inflation pressure. There were some claims made about performance improvements but IMO the conditions necessary to deliver those improvements are pretty extreme and improvements are tenuous.
The information on the function of this pressure balance equipment also ignores the potential for damage to the RV when one tire loses air but the driver is not immediately informed of the loss. There is even talk of serious air loss in excess of 25% of the pressure needed, only resulting in faster wear.
I found no mention of operating a tire that low possibly resulting in a catastrophic failure (coming apart and potentially doing thousands of dollars' worth of damage to the RV).
I can't understand why some would think that lowering the hot tire pressure (decreasing load capacity) would ever be a good thing to do.
Someone will probably point out that some of the systems that connect the air between a set of duals limit the amount of air transferred, but that still leaves a problem.
If you have two tires set to 80 psi and one gets a puncture and starts to leak, the "good" tire bleeds off air to the leaking tire until 5 or10 psi has been transferred. Now both tires are at 70 to 75 psi and are just starting to be overloaded.
But the leak continues and the tire going flat transfers its load to the "good" tire, resulting in the "good "tire seeing ever-increased the level of overload.
This can continue until one tire is flat and one tire is 100% overload. Now you are driving down the road with no knowledge you have a flat and a tire at 200% of rated load.
If you are lucky, you stop and discover the problem before the "good" tire fails, too, leaving you with two scrap tires.
This system does make airing up tires easier in that you only have one valve for the pair of tires, but I'm not sure if that "benefit" is worth the cost.