It is definitely the PoC change causing this combined with married sector logic. However, I really do not think BA has done this deliberately as there is now simply too much missing inventory for this to have been selective. More I think BA has simply not yet got around to entering availability on the vast combinations of sectors available. As an example, LIS-LHR-JFK is available, LIS-LHR not. MUC-LHR-JFK is not available on the same day, but MUC-LHR not. Consequently, having a reservation LIS-LHR-JFK, seeing MUC-LHR available, asking to change to MUC-LHR-JFK on the TATL you are already booked on will be declined. It’s so counter-intuitive.

One reason might be to “protect” inventory commencing at high fare LHR, but this does not carry when differing availability shows from different European markets.