I just checked this out for a trip we have planned to Maine in July.

First, I tried flying from our small local airport. Cheapoair had us going from Indiana to Memphis, to Detroit(?), to Philly, to Portland with 12 hours of flying time and two airlines! When I tried it again a few minutes ago, it gave a rational two stop itinerary.

So, I changed to a larger origination city and it offered us an option with one stop at a price that was $30 better than the airline's own website,,,with the same restrictions (although cheapoair wasn't specific about the amount of the schedule change penalty).