These two documents allow you to clearly define and agree on what will be delivered and the work that was actually delivered. The two lists of items are possibly slightly different if requirements change or new requirements are added mid-project. At that point, you have the choice of being flexible, or sticking exactly to the service order and moving to a new Service Order anything outside of that initially defined scope.
A big thanks to Scott Gillespie from Jigsaw Group for suggesting these and helping me define what should go in each.
https://www.linkedin.com/in/scott-gillespie-712124/
