Can someone shed any light on how accurate and live KVS info is?

Example - currently shows J9 C9 D7 R6 I4 for a flight (BA164 on 25 Oct) but British Airways insist that only D-class tickets are available?

It's not a POS or origin issue as far as I can tell - I played around with adding legs to the flight to see if it moved availability on this leg, and it remains the same.

Meanwhile the other way round, I needed I-class on BA004 on Oct 26th, saw I3, went to book, as I was on hold they all vanished, but after a bit of poking around, the nice BA lady was able to hold one for me from somewhere...