Inter GDS availability is not that sophisticated in regard to "allotments".
Availability for a flight is simply returned as a letter indicating a fare bucket with a number between 0 and 4/7/9 indicating how many seats the airline may wish to issue for that fare bucket for that flight.
What an airline can do however, is restrict availability within a fare bucket based on various factors; region of query/purchase being one. I feel the issue may be with LAN.
e.g. In this case LAN may be making more award seats available for Oz based GDSs rather than those which are North American based.
i.e. If X is an award economy class fare bucket then a query by Qantas in Australia might return X4 while the same query done from Dallas may return X1 or X0.