It appears that the Doo Doo Cats style is not controlled by the Rehearsal Marks.
It appears to cycle based on the Form Repeat number

It plays Doo Doo on the First and Final Form Repeats.
It Swings in any repeats between First and Final.

If you were to initiate the player start at the last few bars (as a short Doo Doo intro),
https://technimo.helpshift.com/hc/en...layback/?p=ios
the next however many form repeats would Swing...except for the final repeat.

By placing a Coda sign near the top of the chart and adding a one bar Coda at the bottom you would have a short Doo Doo ending instead of a Final full Doo Doo repeat.

Doo Doo Swing - Example

)BOB