Let me know if I am wrong...
I start with the standard profile and change parameters A,B,C and D. I save this as Custom1.
I start with the standard profile and change 4 different parameters, E, F, G and H. I save this as Custom2.
I now start with Custom2, slice, print then select Custom1. I now have a profile loaded with ALL 8 changes, A,B,C,D,E,F,G and H??? This seems to be what is happening and ruining prints and hours of time.