I can't answer the supply chain stuff specifically but if you pick up a book on Queuing Theory and skim the results and theorems for simple queues and queueing

I can't answer the supply chain stuff specifically but if you pick up a book on Queuing Theory and skim the results and theorems for simple queues and queueing networks, you'll make these conclusions yourself. I'd recommend one but it's been ages since I was an undergrad and I no longer remember specifics.