I would call or visit Costco directly to see what they do.
Just remember - most "hearing centers" are aligned with certain brands, not totally unlike a fast food franchise. So if you want an objectivity you can trust, get your initial testing done at a medical unit and then go from there to find both people and product that you feel good about working with.
The audiologist I use will indeed do periodic testing and make EQ adjust ents, but I bought a product that allows for that.