I agree, Robert McNewbie does have the basics down and it's nice to see. However, to suggest that the edge requires milling is quite an overstatement. Fact is, as Robert pointed out, the bottom cover is a stamped part. To relieve the edge, the die could easily be manufactured to accommodate the requirement. In other words, zero additional time required and certainly no requirement to place the cover on a mill, to relieve the edge, at all. Further, if indeed the cover required a machining op, which it doesn't, the thickness (or lack of) would not be an issue. A nesting fixture with a vacuum pull would sufficiently hold the cover in position. No need for clamps.
I guess I was just turned off by Mr. McNewbie's statement that 'perception' has 'tricked' the uninformed public as if he has a better handle on just what 'quality' is and then drops manufacturing lingo in such a way as to display his 'street cred'. To a non-manufacturing professional, it might sound impressive but to a true professional, it's amateurish, at best.