The comment I would make is that when they go to the Immigration Appeal Division, it's a de novo hearing. If it takes 18 months between the refusal at the mission and commencement at the Immigration Appeal Division, the Immigration Appeal Division will look at what happened in the intervening 18 months; I would hate to say this, but some of these cases will create a pretty good relationship record in the 18 months after the refusal, so it really doesn't tell us very much about whether the first decision was the correct one or not.
On March 30th, 2010. See this statement in context.