Increase the integral to 50/50 (increase/decrease) and post a datalog of typical idle, slight revving, maybe driving in gear and release to neutral.
I have apsolutely no idea what these integran numbers mean... I had them on 50/50, someone on other forum (maybe here... I don´t remember) sayd that this is too much and lower them 
But as I said, no problem after changing D to higher value.
It's what gives the IAC freedom to move away from the reference curve. Just bring up gauges or graphs of the "IAC int", dutycycle and target rpm to see what it's trying to do.
If you don't give it more room to move than "15/2", no wonder you get a stable idle - it can hardly do anything and is too far away from the target rpm so it always uses the max or min adjustment which is basically equivalent to a fixed dutycycle.
The max/min retard/advance values for the ignition advance idle control has the same meaning, i.e how far it can move away from the ignition table to work towards the idle rpm target.
