Welcome to the LIFO queue!
To be honest, when I needed to have, um, 468 rolled-up elements regurgitated in a specific order, I found it easiest to enter them into a separate table, create a view sorting them as needed, reverse the sort, and finally copy-and-paste the entire column of values into an empty linked-records field so they’d come back up in the desired order.
Was this much fun?
No.
Does it make sense that’s how it had to be done?
No.
Once it had been created and the process successfully carried out for the first time, did it ultimately require a barely negligible amount of attention to fire out a modified rollup order whenever changes mandated?
Yes.