Accuracy phantom drain on active/inactive days

I have noticed something peculiar in these lockdown times. 

My phantom drain (due to power consumption in Sleep mode) is consistently higher on the few days when I had a drive (often short drives), then on inactive days when no drives occurred. I checked and I don't have missing drives which are incorrectly logged as Sleep. In fact, I noticed that phantom drain during long inactive periods is extremely low (around 1 km per day).

Could this be related to the accuracy of Teslafi or could this be real? I drive a Model 3 SR+.