What heater are you using and what is the heater/controller settings vs. actual?
All controllers are hobbiest grade so may vary a little from actual within reason.
More importantly, you also have to be sure probes/sensors have a good flow of water through the full tank, especially in AIO chambers where a heater chamber could get hot, but if probe is in main tank/another chamber, you could have noticably different temps across tank areas. In the EVO 5 specifically, the chamber above pump doesn't have great flow.