It appears that they have gone back to doing the monthly schedule changes on the first Sunday of the month before. All of my November flights have changed, a couple dramatically. American has been very accommodating in giving me basically any schedule change I want. They have even changed the days for me when there was not a good solution on the original date of the flight. I found that the easiest way is to find the replacement flights that I want and use the chat function on the app. I get all my information ready and then copy and paste into the app, and it is usually fixed in a few minutes.