When my oven was brand new it did this
But if you are asking exactly what calibrating means it means when you turn your oven to a certain temperature they make sure it doesn't heat to a lower temp. or a higher temp. It is calibrated up or down to the exact temp. But it would not help one side cooking hotter than the other. It does sound like a coil problem.
(Me?????? Say don't bake?????? :P )