Actually after taking a second look at the sheet and the title of "Flow Switch" it seems to me that it is only going to give you an indication that there is flow. Not the magnitude of that flow. you will likely only get a 1 or a 0 for Flow / No Flow indication. And it will only indicate flow if it is over .5 LPM.

but I could be wrong

Were you wanting something to indicate quantity of flow??
If so, you may need to look elsewhere.