I don't think you're talking about comparable procedures. If you want to change the neck angle, there will be work involved in that whether you have a new neck or not. Further, a luthier will be looking at more factors than checking off 'new neck' on a rate chart. It's not like fixing a car.
My advice would be to check in with a few experienced luthiers in your area (which is bound to have some good ones), show them your bass, explain your problem and see how each would approach solving it.
You may get more specific advice here as well if you can share some illustrative pictures and write about your experience with the bass.