I too take issue with the promises made in the past.
I understand the lifetime licence is for use on a single device, so please don't tell me to read the conditions. I've always understood that, but the specific question of
dual booting with a single licence was asked on February 19th, 2014, and answered by "Advanced Setup Staff". The reply was "As long as they're used in the same computer and not running at the same time then it will work and should not have any issues."
I reached out when my second system lost it's Premium status, on Support Ticket 2645055, but was given the stock reply.
When this was answered back in 2014, you knew that the asker was installing it twice on the same device and it was approved. How can you now say that was always the policy regarding dual boots.
We have been misled!