Please add a Tickbox for the Days when the Tarif is applicable

As we have low and High Tarifs during the week and on weekends it's only low tarifs.

it's really difficult to add that. Could you make it more convenient to do that? 

like selecting the days with a tickbox? so i can pick Mon to Friday for the High Tarif and low Tarif. And for the weekends i can have one extra Line with the Low Tarif for 24h.