I've just created the (dP/dx)/rho via a custom field function and displayed it on an outlet. How does that route compare to the UDM?

I can't get this value because I would have to run for other time steps but I can't do this on my pc. nI've try with another UDF (-v*du/dy) and the weighted average value is the same of the weighted average value of a custom fiel function (=-v*du/dy).n