I like this idea. If only the ground was level! The garage floor slopes out and my driveway slopes down towards the house.You can always put the jack and jackstand on the side of the fill plug, fill with correct amount of lube plus small amount more, lower car to normal, level, position, and let it drain out the fill plug as designed. Then jack back up properly and reinstall the plug.
On my list of things to do when I visit a lift (maybe at Redshift's? ) is to check my fluid levels.