It turns out that the prototype board will be more expensive than I'd thought. For some reason the boards had to be upgraded in terms of minimum trace width (even though that hasn't changed since the test boards) to an extra $55 cost, and the components that I thought would cost about $30 are just over $100. In short, the total that I'd expected to be around $70 is instead almost $200.

I can't blame PCBWay, at least for the latter trouble; they're in China (just outside Hong Kong), and importing most of the components.

I'll still get this prototype, but it won't be until December, and if I have these produced in batches I'll probably go to another company.