When you send a fee to an artist, this is only used to pay them a fee that is owed to them, not to charge them a fee. If you input a negative balance for a fee, this fee will be deducted from other items within the payment and not deducted from the artists' overall balance.

To make a deduction to an artist's overall balance, create an expense and allocate the expense to the artist. You can allocate them any percentage of the expense - allocate 100% to deduct the whole expense from their balance.