I find my grinder settings change from roast to roast anyway depending on the bean i am roasting and the age of the beans from the roast date.
It is not uncommon to adjust the grinder every day.
I am not sure how much a notch changes for your specific grinder but i wouldnt be too alarmed about it.
How does the coffee taste that you roast?
If you have a CS card, what roast level do you roast to?