PLC value do not correspond with actual flow value

I have a error in the pulse repeatability on a Endress-Hauser P 300 Flow Meter. It is about 620 liters out per m3 of flow. 4-20 seems ok but not sure if I should adjust the span to compensate for the discrepency maybe?
That's a 62% error. The K-Factor is the number of pulses for every unit of product volume passing through the meter. You're using the wrong K factor to calculate the flow rate.