Two things ...
1) check the humidity level in your humidor. Your sticks could be too moist. Do a salt test on you hygrometer to ensure it's accurate.
2) Get a new cutter. Xikars are always very good but they do get dull after a couple of years (and no - they don't sharpen them for free anymore but you CAN pay them to do it). I also have the Table Top Quad Cutter that is available here on cigarbid. It give a perfect depth of cut every time.