Not as neat of a discovery, X2. (post cards)

[swarmee]

irv, I would caution you against using PSA 9 prices for cards that are cut from boxes. Many have spider wrinkles from the scissors used to cut them, which would put them at a 3-4 range if they even deserve a number grade at all. The three just shown with red borders would all likely get PSA AUTH, not number grades.
PSA 9s of cereal box cards from the 60s are super rare examples and are priced accordingly by the registry set collectors. Many were probably cut in the past 10 years, not 50 years ago by the kids that originally collected them. Many also have glue stains on the back because of the box construction. For the American Post cereal cards from 1963, it looks like PSA considers the commons in PSA 5 to be worth $3 and in PSA 9 of $60. That's a 20:1 ratio of a 9 to an Excellent card.