I'm confused. You are looking to a oil switch, which can't give you a reading. Your actual gauge is there because you can't get a good reading off the factory switch (which is not a sensor on the W body platform) An odd reading from HPT for it would be considered correct/normal.

Everything is immature...well that's fine and dandy... codes is it saying are immature?

Don't touch a thing until it's got some time on fresh fuel and you have scanned and know what is happening.