At a 25% failure rate, shouldn't the cam grinder take stronger action than to only 'offer' additional services? Something like a strong declaration as to the failure rate without the additional services. Or better yet, make those additional steps inclusive. It would seem to me that the only reason to NOT include those additional and more costly services would because the additional costs would lead to a decline in sales.

In other words, the cam grinder has a responsibility to educate and inform their customers on the issues. Not everyone is up on cam core technology and manufacture.