Z_offset real-time/stored value clarification , please

Hypothetical, sort of. Assuming my probe is correctly configured, I run probe_calibrate which results in an offset of 1.000 and manually store that value in the printer.cfg file so it can be changed. I start a print after the firmware resets tweaking the value by -0.100 from the attached LCD. The print is successful. My questions are:

Do those values represent the same thing (nozzle relationship to probe/probe to nozzle)?

If so, my new manually stored value would be .900, if not it would be 1.100, correct?

Updating that value, restarting the firmware (wiping out the real-time value) should produce the now accurate offset on next print, correct?

I’m having issues with a printer that has been working pretty much flawlessly before upgrading the firmware from 0.8.??? to the latest. I want to fight this a little longer (so I better understand how all of this ties together) before posting my issue. Thanks in advance for your responses.