A single figure of net saving can set the direction of a decision record without settling what the record itself says is at stake. This paper asks what one set of decision records takes an executed calculation to have settled when it weighs a change of arrangement, such as contracting work out, bringing it in-house, making at home, remodelling or relocating, by subtracting the costs that remain and the cost of leaving from the cost that would be avoided. It reads twelve authored cases from AEGIS, a studio of the RISCON family: every case in AEGIS's calculation programme whose run executes that subtraction. All twelve are synthetic settings written in Korean, not real events; every cost, unit and schedule in them is the author's assumption, and the English quoted is this study's own translation.
Four findings follow. The net figure sets the direction of every recommendation, and the one run whose figure is negative is read by its sign in the same way. What the records name as unknown, chiefly quality, further costs and the terms of contracts, stands outside the subtraction. Every record offers a middle option, partial, staged or piloted, and the run gives it no figure, so the trade the records describe in words is never put in numbers. And in a few places the records' units, labels and thresholds for reopening part from their own figures. Read beside the debates on forward-looking costs, on commensuration, on the make-or-buy choice of governments, on contracting out and its reverse, and on the value of waiting, the set shows where one designed record draws the edge of its arithmetic.