I think that's what he is saying but I disagree with his numbers. For 10 units machining plastic costs a lot of money. But you wouldn't do that for 1000 prototy

I think that's what he is saying but I disagree with his numbers. For 10 units machining plastic costs a lot of money. But you wouldn't do that for 1000 prototypes. You would use something like vacuum casting to make the housings and the gears are made from blanks and machined. It might cost you at WORST ~$300 (likely a lot less) for the 1,000 units.