Yes, The manuals could be written much better.

Once the Z3 and Z4 numbers are set, never change them manually- always let the machine configure them. If your post outputs those codes, delete them.

Z1 is the critical number for standard taper cutting and Z1 & Z5 are needed for 4 axis. there are a few rare programming options when Z5 will be used (other than graphically) during standard tapering.

PM me if you have more questions. I'm reasonably familiar with the Mits WEDMs.