I don’t think you should use “detect_binarysensor_status” to handle flow sensor. This function is meant for slow changing events like rain or soil sensor activations / deactivations. In addition, they are controlled by the ‘on delay’ and ‘off delay’ parameters to filter out noise / false triggerings.
As I said, flow sensor events are much more rapid and the sensor can fire multiple clicks per second. This will generate a large number of events. If you treat flow events the same way as rain / soil (which is what binary sensor is referred to), the UI will not display it correctly.
What you should do is to take the average number of clicks over a period of time and log/sample that number. The ‘flcrt’ parameter can be used for that — it counts the number of clicks within each 30-seconds window. You can certainly modify the firmware and the UI code to log this paramerter.