no;  since you are a ratio;  its only the downtime that will effect you... you should be ok.

I do suggest letting it run for the maximum amount of time;  record what the difficulty gets to each time;  average those numbers, and use that as a manual difficulty in your password string.  This way difficulty doesn't need time to adjust every time and keeps you optimal.   Just average ~5 different restarts.
Example password:
c=BTC,nist5,d=4