This is the way those auctions work-the local banks in the area need a supply of dinar to facilitate the daily needs of the citizens and business, they get their dinar from the central bank.
In retro spect, these 19 banks all bought dinar from the CBI by selling dollars to the CBI that were in their coffers. And you can see none of them needed dollars because those lines were zero.
In the past when a ton more dollars were out in the street being used, the auctions showed both dollars and dinar being bought and sold. Hope this helps
They have been trying to ween the internal of the country off the dollar and use dinar more so thats why most of the auctions in the past recent months show banks only buying dinar and very little sales of dollars if any at all.