I also had to overfill a lot to avoid the starvation that caused lifter tick. Oil pan gasket had a leak so I went ahead and put a baffle in the pan and had no lifter tick over 10 runs at my last autocross (with no overfill).
There was never any inconsistency in the dipstick readings I was seeing -- it read dead on the money every time. I would check it per the instructions in my perfectly level garage after shutting down. I checked and checked and checked over minutes, hours, etc and it never moved despite the fact that I could visibly see oil leaking from the valve cover and oil pan gaskets. Would never know I was low until that little light came on!