What is the Price Tier

Thanks for this KT but it is the next selection that is the problem, the one that says Price Tier. When I select that I only get about 12 choices from 0 dollars to $12.99. What does this $12.99 represent when the physical price I list is $24.99 (though none exist, just digital right now) and I want to charge $14.99 for the book? It only allows me to charge $12.99 if it is correct that the $12.99 is going to be the price listed when Apple approves it? Or have I missed something?

New Release. But when I hover, I get nothing.

Thank you, thank you. That did the trick. Much appreciated.