My understanding is that for weight loss, intervals or a more moderate heart rate is better then maintaining so close to your max heart rate. This was described to me by a trainer when I was trying to loose weight. I was tending to run or do gym equipment at a high intensity for 45 mintues at the time. He said I should slow down, decrease time, or do intervals to be most effective for weight loss, particularly if the workout time is longer then a certain amount of time (maybe 20-30 min but I can’t remember what he said). It had something to do with higher intensity for longer period makes your body burn things other then fat for quick fuel. This could be wrong, but this is roughly what I was told a few years back.

I would suggest mixing it up, doing some intervals some day of high and medium intensity, and other days go hard, and see if that changes the rate of weight loss (assuming diet and other factors remain constant).