It seems strange that Buddhaghosa would state that the Kathavatthu contained 500 orthodox and 500 heterodox statements, when modern scholarship indicates there are 252 statements (as indicated in the lesson notes from lecture #4).

Why such a large discrepancy?

Was this some kind of future-proofing and a belief that the uninitiated would not know better?

Interested in speculation or documentation on this particular issue.