Availability is determined by each airline and it's up to the individual carrier to determine how many seats it makes available in L, D and A.

As for the rules, the oneworld Explorer fare is a oneworld product, not airline-specific. As has been indicated, some of the airlines have updated their filed rules for the fare in the past 24 to 48 hours. The others will naturally follow suit, sooner or later.

And finally, interpretation of the rules. Particularly on the section that has been updated by some of the carriers most recently, how one airline reads the rules can be different from another. The oneworld Explorer product is ridiculously complex, so much so some airlines don't even know where to begin. I think pandaperth would attest to this. I referred earlier to QR and JJ really having no clue. In the end I think you need to be prepared to argue how to interpret a rule (as there's at least one or two that are ambiguous, as has been indicate), or go to another carrier. Certainly, int he case of beginning and ending in the same place, that one is quite clear (ie. there are some fairly generous exemptions to this always being the case.