Ok several things about this because it keeps coming up. Brian Gundy has been working with snakes in that area for decades. He knows the ins and outs of the Berkley weather as well as his enclosures and the building he keeps them in. Once you have a stable room that you keep a certain level year round and once you have worked with the same conditions long enough you just know. Somewhat like a professional chef after so many years doesn't need to bother knowing how hot a pan is anymore.
Now on to proper humidity. We don't keep ball pythons in their native habitats so we have to emulate conditions that will allow them to live healthy lives. This means keeping a constant range of temperature and humidity. What hobbyists and breeders alike have learned over the years is that if your ball starts to be in condition of sub 50% humidity in their enclosure they run the risk of developing respiratory ailments. This can also lead to digestive problems and stressed out conditions. On the opposite end of the spectrum, if you were to keep your ball in a 100% humid enclosure with damp substrate and wet walls, it will often result in skin ailment and conditions.
It's common held experience that the ideal range to try and hit is somewhere around 50-70% for their day to day needs and slightly higher for shedding. That is not to say every owner must scramble to up the humidity during a shed. I know several breeders and friends who have kept their enclosure around 60% all the time and still have perfect sheds.
The idea of a 70% humidity increase or a temporary wet hide is a tried and true method many owners use to alleviate the uncertainty of their snakes' shedding process.
So yes, it may be necessary to increase humidity or offer a humid environment hide to shed properly (mine needs this) and yes higher humidity of 50-70% is beneficial to their respiration and over all health but excessive humid conditions can lead to skin issues as they are not semi aquatic mud dwellers like those filthy anacondas!