I ought to know the answer to this, but I've never thought of doing it before.

If I book a Premium Plus TATL ticket with miles, can I then upgrade to Polaris using Plus Points (I'm a 1K) ? The website talks about using Plus Points to upgrade paid economy and premium economy tickets, but not about tickets that you "purchased" with miles. I realize that if the answer is Yes, I'll probably have to waitlist.

TIA for any info.