Actually, the return line orfice is halfway up the center tube, so the housing will only drain partway, and it takes a couple of hours for the level in the filter to stabilize after shutdown. The difference on the dipstick will be about 1/2 quart. The orfice is usually about 1/16" in diameter.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!