Might be one of two things? Either you tried before they changed their policy? Or maybe your car is newer than 1991-1992? Since that would make them 25 years old and maybe that is their cutoff for collector? Who knows.
Also I noticed it greatly depends on the rep you get when you call. The first couple of times I called the reps were less than helpful. The lady I just spoke to today was much nicer and helpful and she actually went and spoke to the underwriter while I was on the line.