A Google data center in Hanau, developed by the NDC-GARBE joint venture, closed within approximately 2% of its approved capex with PROBIS in from pre-construction, running QS, pro forma, and cost control from the start.
By the time steel is on site, most of the capex decisions that matter are already locked in — a pro forma built on assumptions, not a live cost structure, is the wrong tool for that stage.
IT load capacity and floor area are negotiated together with the end user — a cost overrun in one changes the economics of the other.
Distance to a hub like DE-CIX Frankfurt affects connectivity cost assumptions baked into the original business case.
Google and NDC-GARBE need the same numbers, from two different vantage points, without reconciling two separate cost models.