During our visit at Pleasure-Way a few years back, Phil mentioned
that they discussed this matter with Ford - 65 psi front. Ford agreed that there was a handling problem when unit converted to Class "B"
but due to possible law claims they would not change recommended tire
pressure.
On my 2006 Excel TD - tried 65psi but for some reason the front end
was very bouncy - back to 55 and no problems. Also, the stock tires used by Ford are/were Hankcook - Phil was not happy with this brand
as Pleasure-Way received many complaints of handling.