You're correct--the relaxer was on for a total of 20 minutes; this includes placing the relaxer on each section. Once the relaxer was on the entire head, that was approx. 12-13 minutes. That's why I wrote I think she may have low porosity because after the hair was shampooed and conditioned--it still basically looked the same.
I didn't use a comb when the relaxer was applied, so that's probably why her hair did not get straight. In fact, the purpose was not to get it straight or even wavy--just get elongation.