how does an oil pressure gauge/AOS tell you about oil grade and quality?
unless you have an online analyser

I'm assuming the AOS you are using is a recycle design, i.e. one that goes back into the engine?
I'm not sure if you've actually solved the problem to be honest
Oil is still being blown by, you're just putting the oil back in

anyway, question by OP was exhaust, not gauges...we can start this discussion elsewhere