My first post. Sorry for the length.

I am new to exercise. I have been going strong for about 3 months. I have built up from 15 minute maximum to 2 sessions per day totaling 60-100 minutes per day.

My questions are on how to maximize the time I am on the treadmill. So many different options My primary goal is weight loss.

Most days I wake up and do a 30-35 minute run (for me). A quick warm up, about 15 minutes at 6 MPH, 3-4 minutes at 4.5 mph (a brisk walk), another 5-6 minutes at 6 MPH and then a cool down. When I do this, I go about 2.5 miles and burn about 250 calories (Right around 100 calories per mile). All this is at an no incline. Heart rate goes between 110-135.

In the evening I do a brisk walk between 4.5 and 4.7 MPH with no incline. I can sustain this how ever long I want. Most days it is 45 to 75 minutes. I burn the same 100 calories per mile (it just takes longer to go that mile than when I run in the am). So I wind up going 3-5 miles and burn between 300 and 500 calories. Heart rate stays around 110. Towards the end it may hit 120

Recently, I have been using the weight loss program on the treadmill. That alternates between 3.5 MPH at an incline of 3 for 2 minutes and 4.7 MPH at an incline of 9 for 2 minutes. According to the treadmill I burn 200 calories per mile so I burn twice the number of calories per mile as the 2 workouts above. Heart rate is is between 105-130.

Now for the questions:
Does the interval program for heart rate really burn twice as many calories per mile? My treadmill does have different users so I do enter my own weight and height so I always thought the calorie counter was fairly accurate.

If my #1 goal is for weight loss (although I would love to increase endurance as well) should I just stick to the weight loss interval program?

Are there benefits in mixing up the programs?

Should I try something different I haven't tired yet?

Any other advise?

Thanks in advance

I strongly suggest reading the stickied threads.. you'll get lots of good info