Conductance fluctuations have been seen in semiconductors and graphene for quite some time. It has generally been believed that a universality existed in which the conductance variance was the same for variations in energy and magnetic field, although some experiments have questioned this view. Here, we use numerical simulations to show that fluctuations in magneto-conductance are typically smaller than those in energy by as much as a factor of 3. Moreover, the amplitude of the fluctuations in each case varies with the strength of the random potential.