neowin[.]net/news/windows-10-to-start-pushing-crucial-updates-automatically-over-metered-connections-again
It's expected that next week Microsoft will release the final version of 10 that will become the Creators Update in April -- there have been a flurry of Insider builds this week as they push to get ready. One of the changes noted in these latest versions is that setting your internet connection to metered will Not turn off all updates, though Microsoft says that they might only use it when/if an update is critical.
According to what's been released so far, starting with the Creators Update you will be able to delay updates for weeks *unless you have the Home version*. Right now you can set your network connection to metered to avoid downloading updates over an often expensive metered connection, but many have used this just to delay updates. My guess is that it's the 2nd, using it to avoid updates, that Microsoft is trying to [at least partially] stop. For those that use it as intended with expensive metered connections however, it could mean unexpected charges, exceeding data caps etc.
That said, just as Microsoft decided to make this change without notice, they could just as easily, and suddenly, change it back to the way it works today. There are ways to turn off updates entirely, though they're not ideal, so assuming that sort of thing still works with this next version of 10, there may be a way out if absolutely necessary.
IF you know the name of the update(s) [kbxxxxxxx], it's now easier to download them, avoiding Windows Update entirely -- catalog[.]update[.]microsoft[.]com/Home.aspx . That *might* also provide a way out if/when you have access to a non-metered connection, or maybe one that's not near its data cap. [This can also work when Windows Update seems to be taking forever -- this week the miniPC spend 2+ hours at ~40% CPU hitting the 11% mark for update downloads, so I spent less than 5 minutes downloading them to this PC, stuck them on a USB stick, and problem solved.]