I have always heard it is best to dispute during the holidays. Are your chances of getting a deletion really that much greater than any other time of the year? I have some recent stuff (1-2 years old) I was planning on disputing during the holidays in hopes the 30 day limit runs out.
It worked for me. I submitted a dispute with one CRA (meant to be vague) on five accounts. All five were deleted! All five of those still report, 9 months later, on the other two CRA's after many "verified" responses. I filed it 11/28 not knowing that it would matter at all. Newbie luck I guess.