On the dip stick, it kind of depends on how it's mounted and installed. Generally the orientation of the stick shouldn't matter - what's important is that it's seated all the way down in the tube, and it was set-up to measure accurately at that point. If you're overfilling, the
oil level could be high enought where the crank will start "frothing" up your
oil. Typically a windage tray in the pan helps prevent that, but if the
oil level is above the tray it doesn't help much. If it's reading too low, then obviously a different problem.