Disk-integrated reflected-light phase curves obtained under simplified photometric assumptions for the TRAPPIST-1b example considered in this work. The blue shaded region shows the uncertainty envelope obtained when the phase-function asymmetry parameter is fixed (b = 0) while retaining the full photometric model. The red shaded region corresponds to the case where opposition effects are neglected during the inversion stage, allowing the single-scattering albedo to be uniquely inferred at the laboratory geometry and then propagated using the full model. In both cases, the solutions reproduce the same laboratory reflectance at the reference geometry but retain broad uncertainty when extrapolated to other phase angles. The two approximations produce broadly similar phase-curve morphologies, with the largest uncertainty occurring toward small phase angles where opposition effects strongly influence the reflected signal.