I got the Ruby card with the CRO minimum staking. But then I saw that you could earn extra interest if you stake 5000 CRO. So I bought 5000 CRO and then, not finding how to add it to my stake, put it in the 3-month locked interest. But when I check I still don't see the higher interest rates. How can you actually add extra CRO to your stake? Is the only way to upgrade the card?