But Hairy Wheels you clearly are wrong in this case
They started doing retests from 2007 and 2008 with Dekker because his blood values of 2009 where much lower than those of previous years. In other words, he was riding clean in 2009 and therefore his tests of 2007 and 2008 were re-examined.
And in 2008, his results where not bad, as opposed to what you believe, he rode his best classics season of his career in 2008, he was 3rd behind Contador and Soler in Castilla y Leon and 3rd in Vuelta a Pais Vasco behind Contador and Evans. Those where, quite really, the most impressive results in his career against that kind of opposition. And he rounded it off with 5th Amstel (in a lead group with Valverde, Cunego, F.Schleck and Rebellin), 5th Fleche Wallone and 6th Liege.
Yup, that was 2008. And you say he laid off the dope in that year? My god

If you compare that with his 2009 classic year results, it's clear in which year he used dope.
But hey, you probably just went blindly with the article saying his 2008 results weren't good.