Financial Workflows Need Versioned History, Not One Percentage Field

<h2>Money needs explainability</h2><p>A commission amount is the result of participants, roles, weights, policy, timing, approvals, and prior events. Storing only the final number removes the explanation.</p><h2>Snapshot the rule that produced the amount</h2><p>If policy changes next month, an already accepted calculation should still be reconstructable under the policy that was active when it happened.</p><h2>Never make missing allocation disappear</h2><p>If a bucket cannot be assigned, preserve it as unresolved. Financial software should expose uncertainty rather than silently lose value or invent a recipient.</p><h2>Concurrency belongs in the design</h2><p>Duplicate prevention and row locking protect the invariant when two triggers try to calculate or approve the same business event.</p>