I am only looking at J or F bookings on CX.
For quite a long time CX has had the policy of releasing some seats only to Asia Miles and then release them to other FFPs a few days later if they are not taken. I know because some members of my family are MPC and I check on their account. This has been well discussed on FT.
But CX releases a lot of premium seats in the last week preceding the flight. If this new T-6 policy is in place at BAEC it will further reduce availability to BAEC members. That is really bad, especially for regional flights. But I have often been able to move from longhaul J to F close before the flight (paying the small cancellation fee) and that won't be possible anymore.