changing bits and "Zero Function"

[Songweaver1]

I designed a project with three toolpaths; Rough Pass, Finish Pass and Text Pass. The rough pass seemed to go just fine but I noticed that the bit did not return to the exact Zero position I started with. It was above the original position but right over the original Zero. I ran the finish pass and got a more or less decent finish.
However, I think there must be a way to know if I'm beginning the finish pass at the right Zero. Any info on this would be greatly appreciated. I am new to 3d but have made a lot of signs and plaques..... Thanx in advance.

[scotttarnor]

After finishing the Roughing toolpath the machine will return to home, X and Y will remain the same as original home (assuming nothing went wrong that caused it to lose steps) Z will return home also but to the height you set in material setup, see attached bottom field. Z home .png