"invoice" is what the dealer paid for the truck. "msrp" is what ford recommends the dealer sell it for.
It varies by make and model, but the difference is usually 12-17% and that is profit to the dealer. Contrary to what you think, dealers rarley "make money" from car sales. The goal is to sell as many cars as you can, in hopes your customers will bring their vehicles back to them for service.
The dealer gets paid by ford to do warranty work, and out of warranty work is paid by customers.
Service departments are what make dealerships money.