Wow! Reading all of this thread. I see your company needs a massive cleaning up of procedures and practices. I agree that there are too many approvers in your ECO process. I wouldn't even consider envolving Manufacturing or SC into the ECO approval process. Let them have it after it is...
I would give the advice to not base your part numbers (or pair your part numbers) with the part numbers of your client. If they in fact have not assigned part numbers to the parts you are having made by your own supplier, then you will have the freedom to designate a part number as needed. I...