I posted earlier regarding the 10-1000 times price increase sellers ask for XF/S and Gem stamps over a SCV very fine stamp. Looking over many listed XF+ stamps, I realized many are not XF+ based on the Scott Catalog grading guide. Many would only be very fine at best. I could upload many examples of what I said, to prove my point, but you can browse the listing and see for yourself. I think it would be in everyone's best interest for all stamps listed XF and better, be required to be accompanied by a Certificate from a Professional Stamp Expertise Service, such as PSE, verifying the centering grade. Or doing away with the centering grading all together on the listing, and let the buyer decide based on the image posted. As with so many things anymore, it comes down to money, to put XF/S after a stamp is a way to create more money for the seller. Lets all do our best to list our stamps accurately and not mislead collectors into believing a stamp is a gem, when in reality it is a VF stamp.