Whenever I end a print, my filament is withdrawn. That is helpful if changing filament, but it is a pain when doing sequential prints with the same roll of material. Where is the set of instructions being loaded from and can I change it?
Hey, it’s common to edit the start or end gcodes to your needs.
If i do print per print (my extruder is also unloaded after every print), I do a little bit more purging to be sure the extruder is ready to print.
If you do sequential printing (multiple models print part per part on the same bed volume) it shouldn’t take impact because it’s in your end gcode, this should be executed once only in the end of your print.
Here is a start point for your ubderstanding, if you need help the community is happy to help 
:
https://all3dp.com/2/cura-start-gcode-end-gcode/