[kanetw]

The key factor is how fast units need to ship. In general, the scaling is sub-linear due to

1. reduced per-component costs (volume discounts)

2. less administrative/engineering overhead (ie the salaries/one-off costs get divided among more units)

3. more optimized assembly processes

Assembly labor expenses are directly proportional to how many units need to ship per timeframe. If an assembly worker can assemble 10 units a day, you're shipping 200 units/month. So you can ship 1000 units in 5 months or hire 5 people and ship 1000 units in 1 month.