Tool Change Z Probe Only

I am sure this has been asked before, but

It is my understanding that for every tool, unless you have an automatic tool changer that yo0u need to create a new/separate NGC file. Is this correct?

Also, when I change jobs/tool since X-Y does not change, can I just probe Z assuming the material does not change or move? Or, do I need to probe all three with a new NGC file?
Thanks,

It is my understanding that for every tool, unless you have an automatic tool changer that yo0u need to create a new/separate NGC file. Is this correct? YES

Also, when I change jobs/tool since X-Y does not change, can I just probe Z assuming the material does not change or move? YES

Or, do I need to probe all three with a new NGC file? NO