Nope if the oximeter isn’t reporting level correctly then it is a defective device..might be design, might be manufacturing defect. But it has a certain tolerance in it’s measurement it is allowed to vary within...if it exceeeds that it is a defect.
I only know for certain that a blood analysis is much more reliable than any pulse oximeter. In my little story above, those rookie Doctors were remiss in their responsibilities, and I was among the worst of the crew because I failed to call the need of what should be done to their attention.
I had to learn the lesson, years after I had been doing this sort of thing. I was humiliated, but nobody realized it save myself.