If you want to pay off your Current Balance, you can do it in one of three possible ways: 1) with your linked bank account, 2) with a debit card, or 3) with the money in your Atlas Deposit Account.
While your Available to Spend increases if you choose to pay with your linked bank account or credit card, it stays the same if you choose to pay with the funds in your Atlas Deposit Account. The reason behind this is that the funds in your Atlas Deposit Account act as secured credit, and when you pull money from there to pay off your Current Balance, your secured credit goes down by just as much as your payment amount.
Spend Power = unsecured credit + secured credit
Available to Spend = Spend Power - Current Balance
When your secured credit goes down, Spend Power goes down. While your Current Balance decreases after making a payment from your secured credit, so does your Spend Power. As a result, your Available to Spend remains the same.
To learn more about Spend Power, feel free to read the Spend Power article here.