You have to select "High Flow". High flow and High flow next has the same calibration values.
When I try and select "Aqua Computer high flow (53068 )" as the "Sensor Type" I get a value of 29.89 l/m on the OCTO. The high flow NEXT says the flow is 2.57 l/m. Using another standalone flow meter I get a 2.6 l/m value so the high flow NEXT appears to be correct and accurate.