This change seems to have caused problems on Fare Explorer.
I was trying to book flights to Birmingham this weekend and even though the fares appear the system stalls after you choose the return leg fare. An error message appears saying they can't provide the fare try later.
Phoned up BA and they admitted that they had a problem. They booked the fares for us over the phone and waived the £10 phone fee.
Checked fare explorer this morning and it still isn't working.