The Only Person Who Reviews Pricing Is On Leave
Decide what you would do from the brief alone, including whether you would change anything at all. Everything below it is available, but the exercise stops working if you open it first.
Every change to the pricing module is written or reviewed by the same engineer. Their reviews are fast and correct. They start three months' leave in a fortnight, and the payer contract renewal lands inside that window.
Mandating two approvals on the pricing module. It is a policy change rather than an engineering one, it takes a configuration edit, it is trivially easy to justify to management, and it produces an auditable record. The second reviewer has no context, so their approval is a formality — which converts a fast correct review into a slow correct one plus a rubber stamp, while creating the appearance that two people understand the module. When the renewal lands during the leave, the second reviewer is the one who must decide whether a rounding change to a retroactive claim is safe, and their signature on four earlier pull requests has taught them nothing about that.
Read this even if you are confident. It is here rather than behind a button because it is the answer most teams actually ship, it passes review, and the cost of it does not arrive until the change after this one.