Please note that the Lewis while being more expensive was a lot easier to build - from my dodgy memory cells I seem to recall that it was in Man hours terms 1 Vickers to 4 Lewis guns which is why the Lewis (in addition to its utility) was so prolific an automatic weapon in WW1 second only to the much maligned (an unfairly so) French Chauchat.
Well assembly was a lot faster faster, (understandably) not sure about parts manufacture though.