Top left panel: comparison between the |⟨ B_z ⟩| values obtained by analysing the whole spectrum with the Bonn pipeline (BVA) and i) the Potsdam pipeline (PVA, black asterisks); ii) the Potsdam pipeline, but reducing the data with the Bonn pipeline (BrPaVA, blue triangles); iii) the Bonn pipeline, but reducing the data with the Potsdam pipeline (PrBaVA, red rhombs). Top right panel: same as top left panel, but for the uncertainties on the ⟨ B_z ⟩ values. Bottom left panel: same as top left panel, but for the |⟨ B_z ⟩| values obtained analysing the hydrogen lines. Bottom right panel: same as bottom left panel, but for the uncertainties on the ⟨ B_z ⟩ values. The meaning of each acronym used in the labels and legends of each panel (e.g., BVH) can be found in the header of Tables 3 and 4.