I couldn't say for sure, and I guarantee it varies from institution to institution, but I can confidently say that away rotators will always have an advantage, even at the stage of interviews (assuming you did well). Known quantities are better than unknown quantities, and away rotators have the luxury of knowing certian attendings and residents. It also shows a level of comittment to spend a month at a place, as opposed to just a day or two. It shouldn't make a difference, but a program really wants to see that you will go there, and they know alot of people go on interviews at schools they would never plan on attending.