Tire Pressure Chart

x2 on pressuring to max on tire. Provides the maximum load rating and you probably won't notice the harder ride.

Go off the rig and trust the engineer's findings.

The weights on that chart are per tire as noted. But load/pressure also depends on wheel position, as in Single (Front) or Dual (Rear).
Weigh it once, loaded for travel. Divide Rear axle scale weight by 4 and set all four Rear to what the chart calls for Dual. Divide Front scale weight by 2 and set both Fronts to what it calls for for Single.
Note this: It's possible to load the Rear Axle of an E450 to the max load for the specified tires therefore 80PSI.
But! The max capacity for E450 Front axle works out to only 65PSI. Check Ford's label. 65 front, 80 rear. In our case, Jayco simply echoed those numbers on their label. On our first coach, a Holiday, they posted what they thought would work, which was less than Ford's numbers.

Without exception, tire makers including Michelin tell folks to follow the inflation directions given by the manufacturer of the rig. It probably says as much on the chart you're looking at.

Tires are important parts of rig suspension, and Michelin can't know how that factors in to any individual vehicle.

All those pressure/load rating charts can drive a person crazy. Instead of worrying about whether you over or under stopping at every scale you come across and adjusting the pressure every day, why not adhere to the KISS principal?
Not the rock group by the way.
KISS=Keep It Simple Stupid. Simply dictates you should inflate the tires to the maximum pressure as listed on the tires side wall and go on down the road.

You should probably disregard the sticker in your motorhome. At best, the motor home manufacturer has given you the the pressure for the max allowable load based on axle/chassis rating. I inflate mine about 5 psi over the pressure required for the actual load per tire to give a little added safety margin.

It is weight per tire, each bold print weight reading is the start of a different weight rated tire scale, C-D-E etc. The tires on your rig are stamped with the max load they can carry at what psi. Those are not recommendations in the chart, they are the load rating of the tire at that given psi.