It's possible that your thermostat and the Chill show different temperatures. The Chill is a local, directional cooling device: it conditions the room where it's installed, but variations across the room are normal.
In a large room, the Chill cools the part it's pointed at, so another part of the room can be at a different temperature. You can change the orientation of the Chill to balance this out.
Thermostats are usually at eye level, whereas the Chill sits lower, so the temperature can differ slightly between heights.
Sunny windows and open doors also affect the temperature in specific spots. If the thermostat is next to a balcony door or in full sun, its reading will be affected.