What actually moves the ROI

one-way sensitivity · base case 2.1× · illustrative
Adoption rateBuild cost ChurnPrice point Ramp timeSupport load 1.1×2.1× base3.1× 1.4× → 3.1× Adoption swings the case ~3× more than build cost. De-risk it first: pilot one store before the estimate debate (feeds the tree in 39). Even at the worst adoption assumption the case clears 1× — visible because the amber bar stops short of break-even.