Something may (or may not, read on) be a little off in how the upgrade process went through.
I am a Lifetime member. However, with the change, my status now says "Premium" - which is fine, as it remains functionally lifetime and doesn't have an expiration date or anything - but unless I am misunderstanding you, it doesn't line up with the description you gave PWiz.
I will also note that for some reason I got zero points to use in voting for trainers this month. Previously I was getting 75/mo like clockwork, but not this month - maybe whatever it is that looks at an account and automates the designation of points in the database isn't aware of all the possible iterations of memberships.
I was a year-to-year member but upgraded to Lifetime a while back, if that helps at all. Again, trainer functionality and availability are fine, and the "upgrade account" page shows me as having a Lifetime account, it's just the status itself on general pages that says Premium (and nothing else); and, I am not getting upgrade points. I guess just a bug or two to work out with the system there. Best of luck, I'm sure it will be fixed soon.
I was concerned about this as well but after reading a previous post it appears an unneeded concern because the response from PWiz was basically translated, as I understand it, that if your membership is already a lifetime membership it will still be a lifetime membership no matter what it is called now.
I personally don't think "Premium" sounds so bad.. I am happy as long as my lifetime membership is still sound and secure since I am one trainer usin gamer!