My daughter is a distance runner in high school and has had a Forerunner 35 for about a year. It was recommended by a teammate. It does not seem to be calculating her average pace correctly. She did not have it paired to her phone until just last weekend (an iPhone). On her morning workout today, it reported a 7:30 pace, but they were running recovery and it should have been much higher. Sometimes, it will work just fine, but sometimes it will show a very high or very low pace that is obviously inaccurate. It seems to be calculating distance properly, and time is just time, so pace should just be a calculation of that, right? Any ideas? What are we doing wrong?