I have ran into this as well, and don't have a solution but I do know the problem. We had some issues using the measure tool due to the version of fusion we were using and the coordinate system of our map (have since moved to 2.2). Since updating, the measurement calculations are correct but the display of distance and area is affected by the precision that is set in the the measure component.
If you set it to 3, the distance will show only 3 numbers (decimal included. eg. 1.25, 12.5, 125) and once the measurement gets beyond 3 numbers say to 1250, it switches to scientific notation. 1.25e + 3m Area calculations don't do that on screen, but in the task pane results it does. Very buggy.