Column density profiles of CH₃OH (left) and N(CH₂DOH)/N(CH₃OH) profiles (right) of the diffusive model (D4) and a model including three-body reactions in addition to diffusive reactions (ND9). Both models use the methanol formation scheme presented in Riedel et al. (2023). Subsequently, they were redone with a modified chemical network, including the reaction H₂CO + CH₃O → CH₃OH + HCO (NM1 and NM2). The observed profiles are depicted in black (errors as grey-shaded areas).