One article does not constitute "lots", however I will save you the trouble of reading it:

"..in the lab should experience latex resulting in a reduction of rolling resistance from 1.4-5.6w. Rolling resistance should be higher on the road, and thus the savings greater. The cost of rolling resistance on the road could be 50w or more for a 200-pound person. Latex tubes can reduce that cost by 10-20%. "

10% of 50W is 5W, 20% of 50W is 10W === how did you get 20W out of that math, you should at very best use low end as real.

Next:

"We pumped up the tires and rode. We didn't notice the tubes making a performance difference, ... saving even 5w would be hard to measure on the road."

Enough said. All latex tubes will do for you as increase the probability you will get a flat.