Oregon, who manufactures about 90% of all the blades used on mowers, including OEM says the specs on blade sharpness is a 30 degree angle, with a 30 thousands blunt edge. what they call there 30-30
If the chainsaw shop is hogging metal off of chains then they need to find out how to sharpen chainsaw chains, or the customer needs to find another shop to sharpen his chains.
I have seen myself and have had customers complain that they only get 3 sharpening out of a new chain when the shop does it. the guy running the electric sharpener has no reason to take off more metal then is necessary to restore the edge.