We have recorded data on oxygen saturation on actual jumps from 41,000' and 15,000', both in the aircraft and in freefall. The jumpers from 41K have a higher oxygen saturation with their supplemental oxygen than the jumpers from 15K without supplemental oxygen. To my knowledge, we are the only ones to record such data. Actual data and experience trumps theory and speculation. We will continue to record such data. Our systems, both onboard and freefall, provide much more oxygen than is required by the generally accepted formula of 1 LPM per 10,000', and we check all the systems with a flowmeter prior to each jump.
Mike Mullins
West Tennessee Skydiving