Average differences between the input and the inferred atmosphere at different optical depths when adding noise to the synthetic profiles. From left to right, we show the differences for temperature, LOS velocity, magnetic field strength, and inclination, respectively. Colours correspond to the noise values indicated in the leftmost column. Rows are associated with different reference FOVs, with the top, second, third, and the bottom row corresponding to the region inside the orange box, the complete Mancha FOV, the region inside the blue box, and the complete FOV of the MURaM run presented in Fig. 1, respectively.