There is a requirement for fixed pax oxygen
above 14000, and supplementary pax oxygen above 10000.
O2 quantity is definitely considered in FCOM/DDG, route requirements and design (L888 for example). If an operator wants to reduce CPD fuel and standardise diversions at 14000 to the limit of crew oxygen endurance, it will be based on a set minimum dispatch quantity (specified in FCOM/DDG).
In any case,
it does not alter the EDTO area, it is considered separately. Happy to be corrected if I'm missing something!
