Question about Sonnenkönig Fresco 180

According to the manufacturer's website, this unit is designed for rooms up to 77m3, but 115m3 are specified here. Where does this information come from? I have generally noticed that square metre and cubic metre specifications are often confused in air conditioners, sometimes even on the manufacturer's website (De'Longhi, for example). On the other hand, the information on the manufacturer's website with "room size up to approx. 35 m² / 77 m³" seems surprisingly low for a unit in this price range and with 18000BTU?