No problem, @kims, I just used Google Translate to write to people in Spanish, and I hope they understand me too, and I hope that you can understand my response.
I would expect that there is no significant difference, if the input layers are the same, only resampled to different resolutions. As I said before, this model is not doing calculations based on resolution. For example, the value for water yield is in mm, not volume, not mm/ha or anything involving the area of each cell. The slight differences that you do see are probably due to the model resampling precip, PET etc to the resolution of the LULC. It is interesting that there’s more of a difference in water yield between 10m and 30m than between 30m and 50m/70m/100m, but still, as you say, the difference is small.
You could try resampling all of your input layers to be the same as the LULC (and aligned to/snapped to the LULC raster when you resample) before entering them into the model (so the model probably won’t do the resampling process again) and see how that affects the results.
If I’m still not understanding your question, apologies, and please let me know.