I am trying to get DE genes from a scRNA-seq using MAST. The data I am supplying were normalized using scran package. In the MAST vignette, as well as in a separate tutorial, they get a scaling matrix for column sums before running regression and use it as another regression variable, besides the "condition". This looks like another normalization-like step to me. In the vignette, they use RSEM data as input, which, as I found elsewhere, needs normalizing. Do I need this step if I supply data that were already normalized with scran? Thank you.