I have an Asus RoG gamer notebook, with Windows upgraded from Home to Pro (gamer notebooks are killer dev machines with lots of horsepower).
I have tried to upgrade to Windows 10, but it keeps on routing me into the Windows 10 Home area which then conks out when it figures out that this is not a Windows Home machine. I am sure there is a way to get what I want, haven't quite figured it out yet.
So, my experience is the opposite, can't seem to upgrade to Windows 10. And kinda holding my breath what doing so will be doing to my Ubuntu multiboot as well.
I'll bring it to the MS store for them to figure it out after the holidays. Really don't see as worth my time chasing down which illogical succession of screens MS is using to effect this action - it will change again by the next version, I am sure*. I remember having a devil of a time finding the upgrade to Windows 8 Pro for example because it wasn't in the app store but elsewhere.
* I was less than impressed with seeing that a ton of settings have been moved, again, from Windows 8.0 to 8.1, after being moved from 7 to 8. MS needs to understand that there is lot of technical debt, in terms of worthless howto and guidance docs online, when they change basic management steps from release to release. Sure, setting up your system with the help of bash commands can be seen as a bit primitive, but at least that knowledge, once acquired, remains useful for longer periods than constantly changing program locations. Powershell to the rescue?