This is the correct answer. As the resident PDR expert, I will say that crease will not pull out using glue tabs. Those are used on new cars that have metal as thick as beer cans, not our old battle ships. A stud gun that weld pull tabs would be the route I would choose, and then a skim coat of filler.
It could be pushed out using regular PDR techniques, but would require a lot of work and no, a hole would not have to be drilled to get access to the area behind the dent. Remove the bottom of the rear seat and take off that side panel and it's wide open in there. $800 is a little steep. That dent probably would have taken him a couple of hours. You can do the math...