I have the same question. It was showing me the 15,000 point bonus, which expires December 31, 2023. I don't want that, so I selected the 20-tile bonus. I thought that was for next year, but now I went from 50-tiles to 70-tiles this year. I am confused, because the title bonus expires in December 2024, as if I would start the next year with 20-tiles right away?

It is a bit confusing, and needs some work. I just don't want to use a bonus for a year I already qualified for Mosaic as I don't expect to get to 100 tiles.