RV manufacturers usually set the placard psi based on the axle GAWR, meaning the assume the axle may be required to carry its max design load (weight) and set tire pressure accordingly. They don't have any idea how you will actually load the coach when you get it, so they assume the max rated loading. The axle GAWRs are shown on the placard as well, so you can verify that if you like. Also verify the the placard is for the tire size you are using (245/75R22.5). If the placard shows a different tire size, you cannot use the psi values on the placard.
It's common for a coach to weigh in under the axle rating (GAWR) on the front axle, so they required inflation up front is often less than the placard shows for max load. However, it is also common for the rear axle to be at or above its max axle weight. If the actual is above the max, then the psi in the table will exceed the placard value.
Per the 2010 Suncruiser brochure, a Suncruiser 37F on the Workhorse W22 chassis is equipped with a 8,500 lb front axle and a 15,000 lb rear axle. 95 psi would be the minimum for a fully loaded front axle, so it looks like Winnebago added 5 psi to that to allow some extra cushion. For the rear, at max load it would be 3750 per tire and the table shows just under 90 psi for that weight. Only a tiny extra cushion there.
So, your rear axle is overloaded at 15,040 and adding 10% margin pushes it way over the rating.
