I have an Alpine 150 and it does the same thing. I was always under the impression that it was within acceptable limits of the unit. I have the high setpoint on my DHW set to 170 so if it goes to 175 it isn't a big deal. I don't think for a heat demand the unit did anything about 145 last winter so no danger there of overshooting a few degrees.
But I am interested to know if this is in fact a problem?