I re-calibrated my Gaggia MDF last week-end so that 1 matches a notch over 0 (when Burrs touch). I am only able to get a good espresso grind with setting 2. I hear the recommended setting is "6" and I just don't understand how it is possible to get a decent espresso grind with that number as for me it is just too coarse. Does that mean I need to replace the burrs ? I've only had the grinder for a few months and don't heavily use it.