I don't know what the GVW of your Excursion is, but my Sprinter van is 8550 and it come with LRE tires. I can't believe that LRD tires will hold 3000lb per wheel at 65psi. The LREs that I use (Michelin) have a max cold of 80psi, and I run the rears at 79 and the fronts at 65 per factory recommendations.
I would check the tire manufacturer's web site to see exactly what the load rating of your LRD tires is. Another note, rubber valve stems are NOT rated above 65psi, and in some cases....50psi. I would convert to metal stems in any event, as rubber stems can be an unseen source of leakage and blowouts.