Newbie- Amada laser question.

[Falconfab]

Hi everybody.
I hope this question is posted in the proper place. Im learning how to run an Amada laser and Im having a problem.
When I grid out a part Im trying to get the head to rise up between parts. Im using a U1 at one end, and a V1 at the other end of the program. At the last M104 I putting a Z..(whatever) ( ex. M104Z.5) Im told to use a Z.5 but would like to go higher sometimes like 2" or 3".
The problem is this:

Sometimes it works and at other times it acts like it's ignoring the Z.

Anybody have any idea why?
Thanks in advance.
Rick