Ashley repeated them because when she was young, she suffered a concussion where she could not memorize new choreography very well, and this challenge followed her throughout her entire career. That’s why she decided to switch to La La Land at Champs Camp 2018.
She actually never gave that as a reason for the program switch (or for any of her repeated programs I believe). That's only fan speculation. She said she switched back to Moulin Rouge because (essentially) she didn't feel that La La Land was a strong enough program and that Moulin Rouge had more depth.