Calculation of Charge Transfer and results

[Dada]

Greetings!

I am new to bader charge analysis, and I would like to do some test calculations on surface-adsorbate interaction.

I know that in order to calculate the charge transfer between adsorbate and surface, the usual method is to calculate first the bader charge on the surface+adsorbate, surface only and molecule only, then do surface+adsorbate - surface only - adsorbate. I just would like to clarify something. Does this mean that we need to sum the 5th column of the data in the ACF.dat file (which contains the charge values for each atom) to get for example the total surface+adsorbate charge, do the same for surface only and adsorbate only, and then subtract the values? In doing that, I calculated a value of around -0.0003. Does the negative sign means that the charge transfer is from the adsorbate to the surface? Also does this value makes sense, I mean, is this magnitude of 0.0003 still considered as a charge transfer and not something like within the numerical error tolerance and as such practically zero?

Thank you very much and I am hoping to hear from you soon!