So, can we assume that if the production has to be multiplied by 10, the cash flow used for operating activities should also be multiplied by almost 10, giving expenses of way more than $1.4bn?
No, because a huge cost for them right now is underutilization of assets (factory, tooling, some workers, etc.). Their utilization rate will improve, and so operating costs should not scale linearly with revenue growth. "Should" being the key word.
