For the mass models obtained by the transformation (1) of an SIS model, we plot the local slope s = λ/(2 − λ) at the Einstein radius as thick blue solid curve. The dashed and dotted thin blue curves show the mean slope over the interval (2 − x)θ_E ≤ θ ≤ xθ_E, for x = 1.5 and x = 1.7, respectively. For the same parameters, the dotted and dashed red thick curves show the quantity ξ which provides a measure of the deviation of κ_λ from a power law, over the same angular range.