Not measuring actual Flow meter volumes

I have had the water supply off for most of the spring, but not paused any runs and noticed I am still showing usage even though I get low flow alerts each run. I’m assuming after the initial calibration and flow value assigned to the zone it just goes simple math to figure gpm x duration and spits out a total? Why doesn’t the volume actually get totalized off the meter as there can be a decent difference in flow based on pressure swings. Why if it knows there is low flow does it still use the same calibration gpm to give you your total gallon age and not a reduced value? Was hoping the meter would provide more accurate values rather than based on a one time snapshot value. Any fixes or settings I need to adjust to get true totals?

All of these runs the water was off.