Again, forget all logic etc…
Why is ParaView mathematically integrating to a -ve number and OpenFoam is +ve?
I do not understand what ‘flow point of view’ means … Are you saying that OpenFoam multiplies the integration result by -1 for this reason 
It would not make sense for OpenFoam to simply change the frame of reference for the integration when all other result parameter frames of reference seem to be consistent