Thanks for the clarification, everything is clear now.

I'm thinking that I'll call the oral surgeon tomorrow and ask him if he can guarantee that the bone graft will both work and provide enough depth for an implant in the future....

I get the feeling he probably won't want to make any guarantees, so I might as well wait and get a sinus lift down the road. Does that sound reasonable to you?

By the way, do you happen to know if the cost of a sinus lift includes a bone graft as well?