In addition to the observations made by team Joyson, i have noticed that letters b through m all are paired with number 2 while letters o through y are mostly paired with number 1. (y is the only exception.)
Letters a and m are paired with each 1 and 2. Since a and m are twelve letters apart (amongst the represented letters) and they represent the edges of each range, maybe there's some kind of clock theme to this code?
I am suspicious that one of the l2's should be an i2, and that maybe y2 should be y1. Just suspicion, nothing there yet...