Sure, this is always a factor in one`s pricing decision. You can`t substitute the Census for experience. Sometimes from experience you`ll know that a particular copy is impossible to find in high grade, and therefore if a 9.0 copy appears you better jump on it at just about any price because you`re almost certain that a nicer copy will never appear (or even if it exists, will never come on the market). Other times, you know from experience that better copies very likely DO exist, so not much of a premium (if any) should be paid for a 9.0 copy.
I agree completely. In the case of these later WDCS books, I am pretty sure nicer books exist (at least in some cases) and I'm thinking it's probably not worth paying 3x guide for them right now. *shrug* If I'm wrong, I'm wrong.