Um, what makes you think that a full sump will make the oil pressure light go out?
Some newer vehicles have an oil level sensor, but it only goes off when your level is LOW, like a quart or 2 quarts low. That's the only thing I could think of, because as stated earlier, sump level has zero effect on pressure unless it's actually below the pickup tube. My auto shop teacher looked at me like I had asked the stupidest question in the world when I asked what that extra plug thingy was on the side of the oil pan in class, I had never seen one before, and honestly, haven't since.
He does mean well by running the oil at the top fill line, and it's of course best practice. But after 3000 miles and it's a 1/2 quart low, is still pretty damn good for a 26 year old vehicle. and those hash marks are there for a reason, it's the safe operating level for a vehicle, as long as it's in those hashes you should be good, unless you have vehicular OCD, which is a people problem, not a vehicle problem.
Looking back to make sure I got my information right I see he's now banned, so I guess we won't get an answer lol. Which is unfortunate really, he could have learned some things if he wasn't so close minded and stubborn about the way he did things and that his thoughts on the matter were infallible. He had nearly 900 posts, I'm surprised I don't recall him before. If he posted like this elsewhere I'm sure I would have recalled his name, or at least sounded familiar.