When do you check the oil level when changing the oil and filter?
If you check it before starting the engine and adjust the level based on that, then you'll end up low. The oil filter holds between 1/2 and 1 quart.
When changing the oil & filter, replace the filter and add the oil to bring it close to the full level on the dipstick. Start the engine and let it run for about 15 seconds (the red oil light should go off within 5 seconds).
Wait about 1 minute to allow oil to drain back into the oil pan.
Check the oil level again and add enough to bring it to the full line.