A shared operation changes the comparison

Consider a separate constructed service requirement. Two interventions P and Q together and a different complete solution Z are both qualified to supply it over the same horizon. P or Q alone is insufficient. Their subsequent operating, ending and other material consequences are equal; all different costs are payable now in €million, and funding is sufficient for either whole solution. Thus their initial cost difference decides this bounded comparison.

P costs 2.0, including 0.2 mobilization, and Q also costs 2.0 including 0.2. Z costs 3.9. The operating practitioner establishes that P and Q can be performed sequentially during one qualified visit, using one 0.2 mobilization. Required service remains supported during the work; the shared visit incurs no additional consequence outside the supplied account.

The whole P+Q account is 1.8 + 1.8 + 0.2 = 3.8. Adding the separate estimates would prefer Z at 3.9; the supported joint account prefers P+Q by 0.1. That result concerns one actual payment saved through a feasible work arrangement.

Suppose incompatible access windows require two visits and two mobilizations. P+Q returns to 4.0 and Z becomes cheaper at 3.9. If instead the proposed shared visit fails the service condition, remove that arrangement as ineligible and compare any qualified two-visit arrangement with Z. Reducing its price cannot repair the lost service. EAM.11 establishes which visit arrangement is feasible; EAM.10 uses its consequences.

The example does not infer a common saving for CityWater’s separate station jobs. A proposed CityWater sharing arrangement would need its own work, service and financial account before altering the following result.