During my master thesis i compared the influence of different grid-resolutions on the results. The model was not calibrated and i used just the default values. I compared 0.5m, 1m, 5m, 10m and 20m. The difference from the soil loss only is not that big. About 18% between 0.5m and 20m. The difference from the export results are significant.
It shows the sensitivity when it comes to grid resolution, but also just the required calibration for models like this.