https://fourweekmba.com/debt-to-ownership-ratio-steem/ this link might help you understand the debt ratio a little more.
Essentially, when the debt ratio his a set start point, the author rewards begin paying out STEEM as well as SBD. You would see this when you go to claim rewards and you have some SP, STEEM, and SBD.
The percentage of STEEM printed increases linearly until the end point, at which point it becomes 100%. You would see this as a post paying out SP and STEEM. But not SBD.
By increasing the start point to 9% and the end to 10%, it makes the system wait longer to stop printing SBD.
Cheers for that.