We a contractor using the NEC3 Engineering and Construction Subcontract (ECS) with main option A (priced contract with activity schedule). If we instruct our subcontractor not to supply and install various new water services (i.e. it removes work scope which changes the subcontract works information), how does this manifest itself into a quotation from the subcontractor or an assessment from us? Our activity schedule shows rates and quantities. We would also like to know how the resulting residual sums become price for work done to date.