Heres my guess. European pilsner malt has generally low modification, i.e less starch readily convertable in the mash. What this means is you probably need to mash longer. I would mash euro pils malt for at least 90 mins to get full conversion. Plus hotter sparge water will make a big diff as well.
__________________ In The Works: Not enough money to brew In The Carboy: Apfelwine In The Bottles:Apfelwine, Roggenbier, Honey Kolsch, Bavarian Helles