You can't do that verbatim, but there are a few alternatives that get closer to your goal. I've attached an updated version of your workbook with 4 examples of alternative options.
Hope this helps!
side by side.twbx 347.6 KB
Here are a couple more.
If you put discount on a dual axis, you can display discount as a circle or gantt bar on the stacked bar. Just be careful to sync the axis if you are going to hide the dual axis.
If you don't it would look like this
which is a tad misleading because the actual is this:
side by side (1).twbx 369.7 KB