In 2010 my residency changed from the home I own to a home I'm renting, but I owned the mortgaged home all year. Is the deductable amount of mortgage interest paid pro-rated based on the date I moved? This is unclear to me (or I'm optimistic I can claim the full amount of interest for 2010) because I often see the principal residence rule using the phrase "majority of the time". I spent 75% of the year in the mortgaged house and 25% in the rental.
An IRS pub number, section, and paragraph would be greatly appreciated!