I purchased a 590 about a month ago, I've had temps swings and overshoots since day one. On start up it will overshoot 100 to 150 degrees it takes forever to come down to setpoint. This weekend I used it both Saturday and Sunday on long cooks. Saturday I smoked 2 whole pork loins at °225, before I started I put 2 thermo works air probes on the grill grate. They consistently went from 190 to 255 all day just up and down never really did settle, grill was in the shade no wind °80 day. Sunday 3 rack bb °250 setpoint same thing up and down all day long. Is this as good as these grills get or do I have an issue? I've called RT customer support several times all they do is run me through the setting to check that everythings working. Very disappointed with the grill and customer support so far! Looking for HELP. Thanks