Sometimes a saddle will "give" a little - so I often start with the front of the saddle tilted down in front, and then when I sit on the saddle it "gives" so much that it IS actually level.

Often its the taper of saddle and the space between your legs that determines the saddle's fit - more so than the last degree of tilt...... A saddle's fore/aft position affects whether a tilt will increase comfort as well.