Mounts or the process of mounting? Mounting a scope on a double that is not balanced and regulated for it can be an issue. Presumably, the smith at Krieghoff knows what he is doing, but that does seem very high. I priced adding a mount to a Merkel double by the gunsmith at the distributor (also factory trained) and it was far less than what you were quoted.

I would call Champlain and ask to speak to JJ. See what he would charge. Dave