Windows 10 activation fails in paralells 11 virtualisation from working bootcamp copy

Windows 10 activation fails in paralells 11 virtualisation from bootcamp with Windows 10 activated version on it.
Windows 10 seems to think installation harware is different and deactivates Windows 10 when used from parallels virtualisation in mac os.
Parallels support cases (like this: http://kb.parallels.com/9703 ) suggest phone activation for those who have this issue and I did it too and discovered that Microsoft lisence policy allow only one installation per lisence. I got this information directly from Microsoft Technical Support.

So, do I need to buy 2x Windows 10 keys to use it in parallels 11 virtualisation runned from Bootcamp installation, and in Bootcamp?
I have imac27(late2015) with latest updates installed.