Who, at issuance or booking, may close a credit as failing compile rather than as insufficiently documented?

Does the four-slot compile change a booking decision in a way "metrics get gamed" cannot?

Can slot 4 be filled while the verifier's contract still pays on issuance?

Can a credit that passed methodology review still fail an independent reduction estimate?

May a registry issue a fungible tonne-unit across project classes whose independent reduction rates differ?

Does attaching the four slots as a header change booking, or only the documentation of the same tonne-claim?