The Oxford handbook of regulation / edited by Robert Baldwin, Martin Cave, Martin Lodge. (OCLC #435418068)

Why does the paperback record have a series statement that’s not on the piece, and an edition statement that’s never explicitly stated?

Doesn’t matter. The differences between the paperback and hardback are not major enough to justify a new OCLC record. We can just view this as a new printing, and use the (more popular and in some ways better matching) hardback record.