To All 245i cases: Hi Guys there are few reasons that 245i case takes longer then regular transfer for straight cases. One of them if you have filed other type of case before (i.e. amnesty or political or marriaged base case) and then you applied enployment based case and would like to continue with the employment based case but you have already withdraw the previous cases. Regardless, if you have withdraw or /were denied the old cases, INS has to merger all the cases/files together before or during the interview. That means, they have to have the files for all other previous cases with them during your interview which means more time needed to get your old files from the dust and that's why it takes longer to get the interview letter for those who has filed other type of cases. This is according to my lawyer and a friend of mine who applied amnesty case latter got dinied but had a marriage based case, got an interview but has to wait for the other file before he got approved.
I am also 245i and in a simillar situation like all you. Good luck to all you.