Phoenix,
Thanks for the quick reply. I can see Pete’s reasoning since my bed frame is only giving the 2 - 1’ X 3" head to toe wooden support pieces 2 points of support each. The 2 head to toe wooden pieces are 20" in from the side rails and 10" from the center beam, so they are getting some support from the center beam. The frame I purchased is a super heavy duty frame so I think it is more than adequate to support the mattress and foundation and there will not be any problems. I have not heard any creaking sounds yet.
What the PLB foundation needs is a 7 leg, 3 cross beam, steel frame like this one. This would give the 2 wooden support pieces 3 points of support, although none of the pieces would rest directly over the support legs.
So a heads up to those that are thinking about purchasing a PLB mattress and PLB matching foundation. Their wooden foundation construction is not conventional and requires a 3 cross beam steel frame; or as I already posted, post #3, purchase a different foundation.