Honestly, I see this same thing happen with home contractors all the time. My neighbor got a flat fee for a patio and the crew was in and out in two days. Last year they did hourly work on another house and it dragged on for a week with constant small delays. The fixed price just makes everyone move faster and cuts out the fluff. It forces a clear plan that both sides actually stick to. Tbh it feels like the hourly model almost encourages slow work, even if that's not the intent.