OPS.11.1:4.5 - Refine the part that can reverse the choice

Start from the smallest available account that addresses the question. Open a local part when a consequential result depends on its hidden timing, sharing, variation, return or completion condition.

A service block described by a fixed delay can be adequate for a question that leaves its load and resources unchanged. If the proposed release creates congestion inside that block, replace the fixed delay with the load-sensitive account needed for the comparison. Keep unaffected neighboring blocks at their sufficient level of detail.

Changing scope and changing detail are different moves. Adding a subcontractor widens the modeled operation. Showing the subcontractor’s internal batching adds detail. The first can be necessary while the second is irrelevant because the contract already supplies the required response.

Identify uncertainty separately from a deliberate simplification. “The loading time is unknown” calls for an estimate, range or observation if the answer depends on it. “We combine identical loading steps” is a modeling choice whose effect can be compared. C.11.DUA governs whether resolving an uncertainty is worth more than a restricted answer or a different action.