GPA Addendum?

[UMiamiCane]

I wasn't planning on writing one because my poor grades are from my first two years of UG and my last two years GPA is substantially better. I don't have a solid reason for my poor grades, just trying to figure out a balance between college, work, and activities and my course work obviously suffered. I thought my improvement would speak for itself, but when I spoke with an admissions officer they asked if I was writing an addendum. Now, I'm second guessing my decision not to write one. Any advice?