Thanks for helping out snicker! So, You_Too, you might have better results with the average only (as opposed to the average/min/max) script I posted yesterday, and then doing a MergeLuma so the results don't affect the brightness at all.
I don't think this approach is going to get you a Blue Greedo however, as this is pretty much just a first-order approximation.
I'll wait to hear back on your results from experimenting before updating the script.
-G