That's exactly right. OSX-iOS tethering, too. If Win 10 had a feature like that it'd make me seriously consider switching phone platforms.
For those who aren't familiar, how it works is once a client device has connected to a hotspot, that hotspot connection from then on shows up as a network connection and you can bring it up without having to touch the host device. Pretty much the next best thing to having a device with its own cell radio.
So tethering is always turned on, or the ipad can remotely turn it on on the phone?