Before I begin, I'd like to say that I tried the search function, but couldn't find a post that confirmed how I think it works, so I must ask. Here is how I think it goes from my reading of the rules:
Stage 1 - the Summoning
Mage rolls Magic + Summoning opposed by spirit's Force. Net hits on this roll are the number of services the spirit owes. Mage must resist drain DV equal to twice the hits spirit got on its roll.
Stage 2 - the Binding
Mage spends a bunch of nuyen on binding materials and rolls Magic + Binding opposed by spirit's Force x 2. One net hit on this roll is required for the spirit to be bound. Each additional net hit adds a service. Mage must resist drain DV equal to twice the hits spirit got on its roll.
The main thing that seems to be debatable here is whether services owed from the summoning carry over after the binding. By my reading, they do. This has the side-effect that re-binding a spirit is always inferior to summoning a new one to get a bunch of services and then binding it (well, except for how long it takes, but binding already takes hours, so it's negligible).
Izzat right? Is there something I'm missing that makes re-binding awesome?