Comparison of Stokes parameters and PA profiles for our analytical OS approximation against the numerical OS approximation calculated with ARCMANCER. Three upper panels: flux (blue curve), two Stokes parameters (F_Q in red and F_U in orange), and residuals in all three Stokes parameters. All the corresponding results obtained using ARCMANCER are shown with black dashed curves that overlap almost exactly the colored lines. Two lower panels: PA profile and residuals between the results of the two codes. Our results are shown by a blue curve and the results of ARCMANCER with an almost exactly overlapping black curve. The profiles are computed for one spot at a NS with ν_* = 600 Hz, R_e = 12 km, M = 1.4 M_⊙, θ = 60°, i = 40°, ρ = 10°, T_bb = 1 keV, and E = 5 keV.