This article about Kodak Dektol mentions how commercially packaged developers are far more complex than the basic formulas such as D-72 of which Dektol is based on.
Some of the extra components are mentioned in the article as being so minute, that special weighing equipment is required. See the paragraph headed FORMULA TREND.

http://www.flickr.com/photos/camerawiki/5562506733/

I wonder how many components are added to such developers beside a sequestering agent?