Runtastic Calories Burned?

So, anybody that uses Runtastic, I have a question for all of you! I am doing the 5k training and my settings set on running, but because it was my first day of training my speed was only around 3mph. The thing is that Runtastic automatically increased my speed to 5mph because I guess that is what they consider running. So, the calories burned were of course all off, saying I burned almost 500 calories, where in fact I only burned aaround 200 calories. Do I need to set my settings to walking since I am at a pace slower than running even though I am walking and running/jogging? Or, do I just keep it on run and use MFP calories burned for time and speed. Thank you!