Please keep in mind that Bitfinex has a minimum amount of 50 USD for a loan created via the API. Therefore, you can't configure very small amounts as "Iceberg Threshold". Otherwise, your bot will not be able to lend out your funds.
To prevent this issue in the future we introduced a minimum value for the threshold of 100 USD (To add some buffer in case your coin drops in value). The interface will inform you if your threshold is configured to low and will prevent you from saving this value.
We added a chart to the mobile app showing the interest of the last few days. To get this feature, just download the newest version from the App Store or Play Store.