What are you using to judge your calorie burn? A heart rate monitor? The trackers on the machines themselves are notoriously inaccurate. If you are certain you are getting an accurate measure of calories burned, then what you do depends on what your goals are. If your main goal for working out is to burn calories, then you should stick with the routine that burns the most calories. However, if your goal is fitness, there's a lot of evidence that interval training gives you faster gains in fitness.
35 lbs. lost from 1/04/10 to 5/29/10
Size 14 to Size 8, 41-35-44 to 38-28-38
Maintaining Size 8, 39-29-39
Striving for functional fitness!