My daughter is 17 years old, diagnosed with ADHD in 1st grade - we have tried it all, at least it feels that way.
It is true children and young adults, and I would say older adults as well need a lot of structure in their lives or little will be accomplished dealing with ADD or ADHD.
In the 11 years since her diagnosis structure/schedules play a big part in her accomplishments in life.
As we I type she is flying from Atlanta to Washington, DC with a group of FCCLA members to attend a Leadership Training program. The more structure she has in her life the better she copes. Does she always enjoy the structure - no not at all. She tries to go by the wayside if at all possible.
Sounds like you are not unlike me in the fact that schedules and structure are not my forte, especially in my home. As much as I would like them to be, I'm just not the type to put myself out to demand a certain schedule - too many things come into play. But, basically some type schedule does work best. A certain bed time during the week, vs weekends is probably what they are recommending. You will actually find life a little less hectic if you develope this for your son and yourself.
Good Luck and best wishes. It isn't an easy task, but what is... Best advice I can give is work with the teachers, keep in constant contact to stay on top of your childs successful education.
My granddaughter is ADD also, and is in the Gifted class. She drives us crazy with what we have called her headstrong attitude, but is very smart. She has been reading since she was 3 and 4. So don't let the ADD become a crutch, sometimes I feel I did this with our daughter and she uses it as an excuse. But I also see with others help in the school system she thrives and has made it to the level of State Secretary and Treasurer for FCCLA. So good luck with your son and just know you are not alone.