That's correct. You can read the requirements and inspection checklist here: https://lowwall.eu5.org/tb_multi_2023.pdf#page=21Regarding the mares, their manual states that;
Every year or 100 dives:
Take your Mares regulator to an Authorized ñ Mares Dealer for an Annual Regulator Inspection and/or Service. The results of the inspection may require certain parts be replaced or a complete overhaul. Check with your Mares Dealer for Service Guideline details.
Every two years or 200 dives:
Take your Mares regulator to an Authorized Mares Dealer for a complete regulator overhaul. This includes replacing all parts included in the Service Kit.
If you take care of the reg, the inspection should be quick and require no service parts. You can ask your shop what they charge for an inspection where they don't find anything wrong. It should be less than 1/4 the cost of the 2-year service unless your local warranty covers some of the costs of the labor or service kits.