Potential accuracies of retrieving the ozone and nitrogen dioxide vertical profiles from slant-path atmospheric transmittance measurements with the SAGE-III spectrometer launched aboard the Meteor-3M satellite are analyzed on the basis of closed-loop numerical experiments. All conditions of the numerical experiments, namely, the initial data set, methods of interpretation and parametrization of the spectral dependence of the aerosol extinction coefficient, are described. It is shown that the potential accuracies of retrieval of the ozone and nitrogen dioxide vertical profiles depend significantly on the description of the spectral dependence of the atmospheric aerosol extinction coefficient. The mean error of ozone retrieval at heights between 12 and 75 km ranges from 0.27 to 0.75%, depending on the parametrization type. The ultimate accuracy of nitrogen dioxide retrieval in the height range between 20 and 45 km is 0.3-4.6%. The retrieval errors are minimal when optimal parametrizations of aerosol extinction are used, namely, when the aerosol extinction coefficient variations are expanded into four or five eigenvectors of the quasi-empirical basis. The retrieval errors obtained on the basis of the optimal parametrizations are lower than those obtained on the basis of the parametrization proposed by Lumpe et al. by a factor ranging from two to three for ozone and by a factor of about ten for nitrogen dioxide.