That was long processing time for I-140/I-485 concurrent filing in mid-2004. The experience of such filing in 2004 was usually fast, much faster than before 2003. Many got I-485 approved at the same time their I140 approved (which would be Jan 2005 in your case) so CP no longer had advantage over I-485 in term of waiting time since then.
Anyway, it's still approved, even you waited longer than average
Anyway, it's still approved, even you waited longer than average