I'm sorry that has been your experience. I've gone through life asking the same question of different people in different places (In this case - a different section of the forum - because "here" I'm asking for a "Feature Request", where as in the other section it was a general question) and the results are so often positive and beneficial. Sure, on occasion a real dick with nothing else to do will troll ....
That's quite an overreaction to outslider's gentle hint. This forum is low traffic enough that most forum regulars read posts in any of the sub-forums, so posting the same question multiple times is just annoying, and does not increase the chance you will get a useful answer. If you want to further reduce the chances, calling the people who might be able to help dicks is a good way to do that.
The behavior of CHDK auto ISO should be described here
http://chdk.wikia.com/wiki/CHDK_User_Manual#Custom_Auto_ISO although it appears it has not been updated with recent changes brought over from CHDKDE.
You can of course implement any sort of exposure logic you want in script.
