hum, you're wrong or I didn't undersand, your module works on the selected layer, not on every layers...
The modul8 object has two methods:
setValue(keyframe,value,layer): Can be used to change the value of a Modul8 keyword
getValue(keyframe,value,layer): Returns the value of a Modul8 keyword
For example to change the value of the color modulate:
So I think 0 is for the selected layer, 1 for the first, 2 for the second, etc. (is it correct?)
If you want your effect only on one layer, you have to change the code, I don't think there's a way with setValue...
But... I really don't know what to change in your code.... I told you what I understood but I have many things to dicover too
so good luck