Dunno if I'm stating the obvious: a significant amount of oil is hung up in the engine after shut-down. I don't look at the oil levels for accuracy after shutting down. I find I'll "gain" around a half quart letting it sit. I only track the oil levels when the engine is cold.
On my V, I only add when I'm at or below 6. On my last annual, I had them only add 6 quarts (+ 1 pint of CamGuard) and it's stayed that way for the last 12 hours.
Keep in mind, the sump is legally required to be sized for the maximum endurance of your airplane while consuming a quart per hour + minimal operating amount. On our planes, that's a minimum engine requirement of 2 quarts + 6 quarts endurance = 8. As we all know, the top of it just gets blown out.
