They're paying me for the results. Not for the hours.
Thinking that they'll "ramp up the required results more and more until you are working 40 hours a week" means that you're still thinking that you're paying for hours.
Still, it's the responsibility of all employees to improve the process that they work in, just as part of the company's continuous improvement. Which means that more/better results will be delivered over time anyways.
How do you agree on results that are "enough for the company" when you hire a consultant (assuming they're an intelligent consultant and don't charge by the hour).