800 rebanding

I've got an old 780 that I've been using since moving to South Carolina on the Palmetto 800 system. They are in the process of rebanding and just did the sight closest to me. I was under the impression the 780 would no longer track but I programmed it in to see what would happen.
It tracks the new system just like the old. The frequencies went from the 860 and up range down to 851-853. Can't explain it but it works fine.