Tim, I believe you are mixing up two unrelated features with two different products.

Yes, the picture comes from meprog; I am aware of this because I have it. The meprog allows you to program that incrementable "serial number" into any location you wish. You may program it into the "run-time unreadable" PIC ID Location if you want--but you don't have to! If you want to read it during run-time, then it would be advisable to find a different location to program the serial number to. Again, Meprog allows you to specify any location in memory. The last memory location (or near it) is an easy one, since you can be certain you aren't overwriting code (unless you have a bootloader).

Just because the PIC has a "serial number/ID" location does not mean you have to program the meprog "serial number" into that location. They are two entirely separate--yet compatible--features in two different products.