Keep in mind that Amel is a boat builder and not a parts supplier or a shop. The fact that they supply parts makes them a better boat builder but they do have to charge the logistic costs to you as well to keep this a viable process. For them these ad-hoc logistics are quite a disturbance of their primary process.
Shops typically have deals with logistic partners to keep the transport costs down. I don't think Amel has enough volume in parts to do such a thing
When I owned a Hallberg Rassy I found out they actually had someone start a separate company to deal with all these requests. On itself a very clever idea that may work for Amel as well but they charged decent money as well to send things over.
So yes I agree it can be annoying but I praise the service Amel provides us with helping us to keep afloat.
Just my 2 cents.