please explain where that 14.6% Oxygen in the stack test data came from?
The heat source (butane like fuel) is combusted in air, nominally about 21% oxygen.
Some of that oxygen (about a third of it) combines with carbon, hydrogen and nitrogen, creating CO, CO2, NO2, NO3, H2O.
The rest of the oxygen in the air is re-emitted out the stack.
"Give me your tires, your plastic,
Your 20 ton masses yearning to be cracked,
The wretched refuse of your 7-Eleven stores.
Send these, the oxygenless, trashcan-tost to me,
I lift my secret catalyst beside the P2O feedbin door!"