Freddie Mac late last week announced expanded programs for buying interest-only ARMs, arguably the hottest product in the mortgage market over the last few months of 2004 and early 2005. According to data compiled by Inside MBS & ABS, some $206.0 billion of interest-only mortgages – mostly ARMs – were securitized in the non-agency MBS market last year. The IO share of the non-agency MBS market jumped from 15.4 percent of total issuance in the…