Yes — based on the feedback provided, $20 for one roll of 120 black-and-white processing with a contact sheet is considered reasonable, especially from a quality lab. Medium-format film lab work includes chemicals, handling, processing time, quality control, and producing the contact sheet, so you're paying for both materials and skilled service. If you rely on a lab for convenience and consistent results, that cost is part of using film. For professional work, it should simply be built into your pricing; for personal work, it's part of the ongoing expense of shooting medium format. If the price feels too high, that may be more about the overall cost of shooting film than this particular lab fee being unusual.