The calculation of the inverse scalelengths $R/L_T$, $R/L_n$ may depend on the choice of the radial variable, depending on the definition of the scalelength. The value of $\lambda_T$ and $\lambda_n$, as defined in [O. Sauter {\it et al}, Phys. Plasmas {\bf 21} (2014) 055906], do depend on the radial variable used in the exponential. We discuss the various options and the typical values obtained with C-Mod and TCV equilibria.