Hi Sage,
you are correct in what you say, that is the main problem of incremental code, as the code is written to do that job then the code is safe, if it is to be adapted for other jobs then all the rapid moves have to be checked and adjusted for safe movement.
If this was going to be a regular problem then the g-code can be written using # codes to allow the code to be altered by the changing of a variable.
CNC is about repetition, we write a g-code program and prove it works, we then save it for the next time we make the same part, if the code worked the first time it will work time and again.
As with lots of things in this world there are many ways to do a job, finding a way that suites your way of working is the hard bit.
You have learned a lot from this exercise already, just think what you may learn tomorrow.
Graham.