You are telling the truth which most 887 applicants understand.
that is what the DIAC did recently esp after Feb 2013 as they started assess the priority 5. Before that, nobody could say the processing time of 887 is longer than 189 or 190. Even than, 887 is priority 1 before 1st July 2013.
Conclusion, the policy in DIAC is totally changed recently re processing 887.
I called the DIAC today, and the Lady in Sydney service centre with accent told me the 6 months was after the allocated date. I told her she was wrong, and then her supervisor picked up the phone to confirm 6 months means processing time after your lodged date.
Therefore, Brisbane processing centre should be the office with high complain.