Your circumstances aren't so extraordinary to justify an addendum. Like many people, you had moments of laziness in your undergrad. Don't try to pass it off as immaturity, it just looks like a transparent, weak excuse.
My UGPA was ok (3.4, Politics, Big Ten), but it definitely shows that I took advantage of large lecture halls without attendance rosters (aka sleeping through class) and the abundance of extremely cheap happy hours ($1 pitchers!). Since then I've taken some grad courses (no degree) PT while working FT and have a 4.0 in those. Is it worth writing a GPA Addendum talking about how now that I'm "grown up" and working, I've matured into a disciplined person able to work hard and get good grades? I know these addendums are more for people who got solid C's one semester because of taking care of their terminally ill family member, but I didn't know if it was worth it here. Will it just highlight that I could have tried harder as an undergrad (and maybe will revert to my drunken ways in LS) or will it paint me as someone who's now ready to hit the books?Overall I'm trying to highlight my appiclation as a "mature" 26 year old. Not quite Non-Trad, but still more disciplined than a 22 yo straight out of UG.
i dont think you need an addendum, they are for people like me who partied through college the first go around and now (due to LSACs future crushing must have all transcripts ever, no matter how old they are rule ) have a sucky LSAC cum GPA to explain away