Distribution of lags τ measured on the fiducial light curve for different realizations of time variable microlensing (cf. Sect. 3.2). Left: distribution of lags τ using (Eq. (6)). Right: distribution of lags using Â(t), and assuming that the lag τ< 210 days as suggested by the left panel. Each panel shows the result for three different spline models of the extrinsic variability, and applying the same procedure to the fiducial case where microlensing is constant over time.