OK here's a short rundown of the 2 AFCs:
Old-school AFC is very simple... it has an adjustment range of +/- 30% at 5 fixed RPM points. Each RPM point is adjusted by a knob on the front panel of the unit. The knobs are 800, 2400, 4000, 5600, and 7200 RPM. The AFC interpolates at RPMs between the knobs (i.e. it draws a line to "connect the dots"... so at 3200 RPM, it would use a correction % that is halfway between the % on the 2400 and 4000 RPM knobs). It is very simple to use, but it is really limited to WOT-only tuning because there is no provision for part-throttle operation (it doesn't even consider throttle position, it is just a map of RPM vs. % airflow correction).
The newer AFC (blue screen style) is a bit more complex to set up, but has a lot more capabilities. There are 8 RPM points (instead of 5), and those RPM values are user-defined (you can set them wherever you like). At each of those RPM points, you can program up to +/- 50% airflow correction for both High and Low throttle. The new AFC interpolates when between RPM points by drawing a straight line, just as the old AFC does. The new AFC also uses throttle position to switch between the low-throttle and hi-throttle values. You tell it what throttle percentage defines "high" and "low" throttle. When between the "low" and "high", the AFC will interpolate between the low and high maps, and when above the high point, it uses the high map exclusively. The new AFC is a bit more complex because it is a three-dimensional map of RPM vs. throttle vs. % airflow correction. It can do a lot more than the old AFC can, but there is more of a learning curve before you understand how it works.
I use an old-school AFC on my car, but someday I might make the switch to the new style. I understand how it works already, so it shouldn't be too bad to get used to.