Way faster windows updates if you have more than one machine

I have 6 PCs. When a big windows update comes out, they all try to download it through my 33Mbps internet connection. It takes a while. I noticed a setting under windows update called "delivery optimisation" which was set to "allow downloads from PCs on my local network". When I changed it to "and PCs on the internet", it actually did so (from my own PCs, on my local network). Looks like Windows 10 can't tell the difference between a PC on my local network and one on the internet. They're connected together through two gigabit routers, one at each end of the property. They can all see each other with windows file sharing and are on the same subnet, IPs created by the main router which is the fibre internet one. Oh well, it's doing it properly now, so I suggest you do the same if you have many computers.