Neos: Transactions - Requests for Deposit increase the amount due

When adding a transaction to a value time with an amount due and requesting a deposit, the amount increases the amount due rather than reduces it. I have to edit the transaction after it's created and change it from a credit to a debit in order for it to properly reduce the amount due.

This appears to go against accepted accounting principles where a received payment is credited to an amount due which lowers the amount due.