The EPC contractor knows the contract, the site and the schedule better than the owner does; that asymmetry is where cost and time are lost. Our practice closes it on the owner's side: a project management office that reports weekly against baseline, a design and procurement review that catches the long-lead items before they set the critical path, and a change-order and claims discipline that keeps the contract's price the contract's price.
Acceptance is where the practice earns its fee. Provisional and final acceptance, performance ratio and availability tests and the warranty period are managed as contractual events with evidence, not as site milestones; a plant that is mechanically complete but has not passed its performance test is, for the loan agreement, not complete.