In the current paper we describe results of an extensive and refined analysis which shows that the beaming leads to considerable changes in the model line ratios and brightness estimates. For example, beaming shifts the locus of the brightest masers to the lower values of the gas densities. Recent theoretical paper by Leurini et al. (2016) presented extensive consideration of the Class I methanol maser (MMI) pumping. Their study allowed to distinguish only 3 of 4 MMI pumping regimes found in Sobolev et al. (2005) and Sobolev et al. (2007) on the basis of analysis of observational data combined with theoretical considerations. The regime when the line from the J-2 - (J - 1)-1 E series is the brightest was missing in Leurini et al. (2016) results. This may be explained by considering the fact that the authors did not take into account considerable beaming effects.