I am trying to return a daily total of flow through a control valve. I am filtering the data based on 2 things, 1) the valve output must be greater than 0% (meaning the valve is opened/opening) and 2) the flow must be reading greater than 0. On one particular day it returns a value of "-0.0917". How is this possible? am i missing something extra? I have attached the data link screenshot below. Thank you in advance.