Explain every movement in margin against last month

A margin percentage on its own tells a director nothing; what matters is why it moved since last month. Carry the previous CVR alongside the new one and write the reason for each shift: a variation agreed, an accrual that proved high, a rate over allowance, a claim that firmed up. A margin discovered to have fallen at the final account is a disaster; one seen to fall a point a month, with a named reason, is a job being managed.