Whoa! The Chaodao article is interesting, but the topic here is pu'erh, a fermented tea that is noteworthy for it's medicinal action. It's not the same as the unfermented teas tested in the articles cited in the CD article.
Fermented sheng and shu are widely known to have lower levels of caffeine relate to unfermented tea, lending itself nicely to after-dinner consumption. Caffeinates are apparently biotransformed in fermentation process. Plus, with a 20s rinse, you're discarding as much as 20-30% of the extractable caffeine in a young sheng or shu. That reduction might be enough to make a significant difference in effect because caffeine physiological effect occurs above an effective threshold concentration in blood that will vary with age and other factors. Plus, you have inhibitory neurochemicals in pu that counter the caffeinates and glutamate excitatory buzz effect.
Source:
http://users.argolink.net/purfarms/komchem/teacaff
PU-ERH, Caffeine Content, % of Total leaf mass
Green Pu-erh (4/2000) 1.7
Large Leaf Aged Pu-erh from Old Trees (4/2002) 1.7
Loose-leaf Pu-erh (4/2000) 1.8
Aged Green Pu-erh Brick (4/2000) 2.6
Tibetan Mushroom Pu-erh (4/2000) 3.0
1st Grade Pu-erh Tuocha Camel Breath (4/2002) 3.1
Pu-erh Tuocha Camel Breath (4/2000) 3.4
Note that the dense tuocha are at the high-end of the test value range.