We just came back from a trip yesterday, and all of the service was fantastic even though we were on the (deluxe) dining plan.
I thought that all of the servers were knowledgable. Most mentioned the dining plan immediately, and reminded us what was and was not included. Everyone was more than helpful to provide the necessary bill(s) to sign, depending on whether we wanted to pay cash for the tip or charge it to the room.
In one instance at the Flying Fish, I asked the server to spli it up so that we could charge our wine to the room, but pay cash for the tip. So I ended up with the bills - two to sign and one for the cash tip. He set it up for me quickly and with no problems.