What controls drawing zone numbers?

I have been working on creating new borders for my drawings but I have been getting odd zone numbers and letters and I can't find a way to change them.  Instead of 1-2-3-etc and A-B-C-etc I am getting 2-4-5?

I have looked that the "Zone Parameters" in the "Sheet Properties" and the "Drawing Sheet Properties" but I haven't had any luck.  I don't understand it.

Does anyone have any insight about this?

Thanks,

Pete