I have my unit measure set to miles. When viewing "Activity per Month" or "Activity per Week," the unit measure is displayed as "miles," however the numbers shown are the distances in kilometers. For example, I ran a 50K a couple months ago. My totals for that month show I ran "50.01 miles." There seems to be a bug where the preferred unit measure is displayed, however the values are not translated to and displayed in that unit measure.