Am I using the credit wallets wrong while spending on my card?

NexoNexo
$0.60757
4.19%
self.Nexo1m ago
I thought I had understood how credit lines worked when making purchases on my card but it’s not doing what I expected. I moved a chunk of my Nexo tokens into my credit wallet, with the plan being that I could use these for collateral for card purchases while still getting 7% interest on my tokens. However when I make purchases, my polkadot is being pulled from the savings wallet into the credit wallet automatically and is being used as collateral. Meanwhile I’m still able to move my Nexo tokens back to the savings wallet, which I assume means they are not being used as collateral even though they were already in the credit wallet. How can I use my Nexo tokens as collateral for my card payments? What am I doing wrong?