Relative differences between survival probabilities of He (upper panel), Ne (middle panel), and O (lower panel) calculated using the analytical and the full time-dependent models. The time-dependent model is identical as used in Fig. 4, the analytical models were calculated using stationary ionization rates following the 1/r² solar distance dependence, with the rates for 1 AU calculated as average values over intervals ending at the detection moment and spanning backward in time 1, 3, or 13 Carrington rotation periods. The relative differences do not average to 0. This effect is most visible for O, for the entire time interval shown in the figure. The systematic upward departure of the mean values from 0 is due to electron impact.