Obviously I don't know what molecule you are looking at, and I don't know what results you saw. However,by and large your input seems correct. Limitxyz specifies that you are going to plot data on a grid ranging from -12 to 12 (101 points) along the x, y, and z-axes (i.e. a total of just over 1 million points). Can you describe the differences you are seeing?
Huub.