Those are great prices. The question is; Will he let you do your own oil, fresh water, AC, and then do the clean up that you normally do before it gets covered in the fall and again before you launch in the spring?
I don't pay for winter storage either anymore. When I was in a boatyard it was required that he do the oil changes, and winterize the fresh water system, head, and AC as part of the deal. It made sense because of the way he hauled boats out and stored them when he was done with everything. To let owners jump in the middle of everything and then come back to the boat for shrinkwrap would have screwed up his whole system. He lifted a boat, and it stayed on the lift until after everything was done, it was wrapped, and then tucked away in it's winter spot. Then he moved on to the next boat.
Waxing the boat out of the water was not an option for the owner in the fall because that would mean he would have to block it up somewhere for you, then come back and get it again to bring it in to the building to wrap it, then bring it out to it's winter spot.
He had no problem at all with an owner uncovering the boat in the spring and detailing the boat himself or making minor repairs or modifications as long as the owner was neat and didn't bring in any outside vendors that didn't come through him. That was very fair. Many places won't even let an owner do that much.
When I was looking around for places to dock a few years back I went to one place that pretty much refused to let an owner lift up his own hatch while the boat was at his dock or in the yard.