just looking around a bit i found this :
"The red line is affected whenever you win or lose a pot without getting to showdown.
- Every time you fold before showdown your red line goes down.
- Every time you bet and make your opponent fold before showdown your red line goes up."
you can read the rest here, no idea how old this is, but may be helpful - http://www.thepokerbank.com/articles/software/red-line/
Also, 2.1 AF is not all that aggressive. still a bit on the passive side of things. Leakbuster for instance gives a recommended range of 2.3 - 4.1, but i'm not sure of your sample size, and it may even out.