No... What's the size? 256, 196, etc... The number '6144' and '5888' refer to the units in the cartesian plane(your map). Don't refer to those units, "6144 - 5888 = 256' looks like a huge amount but is too small because it is only 256 units in the cartesian plane. I noticed already that you used the per-unit in the cartesian plane because map sizes do not exceed 256.