Ask them what procedure they use. There is really basically two, flushed or drop the pan and change filters. I wouldn't trust a shop with either, I would do it myself then it will be done right. Drop pan replace filters, do not start truck yet (make sure the pan is sealed back using atf let cure) put back fluid from neck, dont start truck yet, go too cooler lines and unhook and put over bucket, now start truck until fluid starts coming out clean while someone is slowly dumping in quarts down neck. Or you can turn truck off and on a qrt at time if someone can't help. Only that way is 100% of the fluid replaced and new filters. No shop does this that I know of, and certainly not for 230 bucks. Use redline ester fluid, learn more Syn thread. If you might do it yourself let me know I show you the youtube on it.