Ability to buy more sitting days

Hello,

Long time player here.

I have just returned from a short stint away and due life commitments/work I have to use sitting days for my prov a fair bit. I am hoping you can please look at introducing the ability to purchase more sitting days from the shop?

Eg. Sitting days over the 21 days cost 2x credits or something along those lines.

It would make life easier knowing I can continue to play and not worry about my prov and how many sitting days I have left, especially when in war.

Thank you

Thomo