Metered connections on Windows 10 post Creators update install:

For Windows 10 Users on tablets and laptops that connect via phone hotspot or other "low download quota" services you need to be aware that there has been a change in the way that Microsoft handle windows updates over "metered connections"

This page tells us that: 

"A metered connection is an Internet connection that has a data limit associated with it. Cellular data connections are set as metered by default. Wi-Fi and Ethernet network connections can be set to metered but aren't by default. Some apps might work differently on a metered connection to help reduce your data usage. Also, some updates for Windows won't be installed automatically." 

As you can see by the description and by the screen shot below, some updates will still be downloaded even over a metered connection. This is a change from previous versions of Windows and may cause you consume more data than expected especially if you use multiple PCs connected to your "low download quota" service. 

You need to be aware of this and ensure that you have enough download quota to cope with the demand.