Tire manufacturer's specifications
Getting back to the original point, the tire manufacturer sometimes suggests a different pressure for their product. Call them and ask. Michelin's representative (800-346-4098) said to use the pressures in the owners manual. Also said that there is no difference in tire life for a solo rider when using the "B" rating Pilot Road 3 versus the other rating.
when I told her how much I weighed and what I usually carried, she said I could adjust the pressure upwards near the "loaded" recommendation.
So I guess my point is that the numbers in the bike's manual are for the original equipment tires and your after market tires might need a different pressure. The tire manufacturers are willing to explain this to you so look up their phone number and call.