How to Upgrade to one machine for entire Home Network

I have a limited data plan so I want to conserve internet use as much as possible.

I have two laptops identical in every way including the applications that are installed on each. They are both on my home private network. My question is: If I download Microsoft upgrades in the normal way from the Internet to one of them, can I avoid doing it on the other by setting it to get the upgrades from the first one rather than over the Internet? On both machines, I've set updates to "Allow downloads from other PCs on my local network." I don't know how this works, or if I need to do anything else, so would very much appreciate advice. Thanks in advance.