Ratable, usage and milestone patterns; contract modifications treated prospectively; deferred revenue that ties to the ledger; and the operator metrics computed from the same contracts.
Performance obligations, relative-SSP allocation and recognition schedules that sum exactly, posting their own entries.
Amendments create a new contract version; the old one is superseded and stays readable. Revenue already recognised is not disturbed.
MRR movement, NRR and backlog derived from the contract schedules, reconcilable to revenue on demand.
Each of these is a product page describing code that exists.
A seeded company, a close in progress, and every number computed by the engines.