When I got my 1860 halfpenny graded by CGS I checked their website for prices equivalent to specific grades. The finest known at the time was a CGS80, I didn't expect mine to come up to that grade, at the time a CGS80 was valued by them at £750 so you'd assume my apparent "finest known" graded at CGS82 would be around £800-£1000, but nope, everything went backwards, the CGS80 is now £500 and mine now at £575