I don't see why testing at level 2 could have an impact on certifying for level 2?
When you try to get a certification for a certain level, but you already perform some activities from a higher level, your company may benefit from it. In addition, reaching the next higher level should be more easy.
In general, this is the benefit the continuous representation offers when compared to the staged representation: you choose which area's you want to work on, regardless of a level. Certifying will look on the maturity of the choosen process areas, not the prescribed process areas of the staged representation.
More information at http://interactive.sei.cmu.edu/Featu...ight.dec99.htm