Should I be looking at a different `reference` tag here? The commented-out code named `reference_low` and `reference_high` but I couldn't find those anywhere in the C32 spec; I'm assuming they're part of the CCDA spec?

I couldn't find anything specific enough about how reference ranges work in the C32 spec, so I turned to ol' faithful: http://motorcycleguy.blogspot.com/2012/08/moving-on-from-c32-lab-results.html