I was getting a CEL with codes that pointed to vacuum leaks (and the oil fill tube was leaking) but the CEL remained even after the leaks were fixed. This was on my 2000 S. I got frustrated and bought the Durametric but couldn't understand the readings and eventually posted my numbers over on the Pelican forum where somebody commented that my readings looked odd and he thought I might have a bad MAF sensor. I bought a new MAF sensor and it instantly cleared up the problems and my Durametric readings went to normal values right away.
I'm not a technical expert and hesitate to give advice but I can say that my car was helped enormously by replacing the MAF sensor. I tried to clean it without success but a new unit worked wonders. And there were never any MAF specific codes being displayed, just fuel adaptation range limits being exceeded. The Durametric wasn't very useful in performing the diagnosis but it did work well to prove the MAF replacement was indeed the fix because the before & after readings showed such a huge improvement for the fuel adaptation values. Those were the FRA and RKAT data points.
Here is a link to the thread on the Pelican forum.
http://forums.pelicanparts.com/boxster-cayman-forum/600891-bought-durametric-but-i-need-help-understanding-numbers.html