I know this "should be" simple, but ...

I have a CCPU that is losing approx: 6 minutes a month - I've tried two different NTP servers - one time server resets the clock to a hour ahead and one 2 hour ahead when they update

I'm not sure what to do - both NTP servers are Central Time Zone servers (Chicago and Oklahoma, I'm in Nashville TN) - obviously I don't know something critical and was hoping someone here would help me fill in the blank

Don . . .