I have heard about that several times, but never tried it myself. The intake port on the pump in fully closed before the pressure port opens. My guess would be, assuming crank position actually makes a difference, if the pin is at the top, the oil is not going to try and siphon out into the sump. If the pin was at the bottom of the stroke, that would help create the siphon effect. I’m reasonably sure some oil finds it way past the quill regardless of crank position. Especially if the timing cover is mismatched and the side of the quill is worn. My Comet sumps fast enough that it would be a good candidate to measure. Drain the sump… let it sit for a week at BDC… drain and measure. Repeat the test for TDC and measure the difference.… but I’m all tested out for a while.