Bear in mind that the Charlton catalogue only give an estimate of a note value and is at no time an actual note value. The price of a note is set by offer and demand. The only problem demand can not be evaluate these day because the many so call “auction” start at a price almost equivalent to the price publish in Charlton and on top of that you need to add a buyer premium often reaching 20% + all applicable taxes, so it's not the best way to evaluate the true price of a note. If you compare the price of a note ten years ago the price almost double, did demand raise to that extend, or something else is pushing the price upward, maybe collector that as been in the market longer then me can give their opinion, if the market can hold such a jump in price?