When true, fees are deducted from usd_amount instead of being added on top, so the total amount debited from the account equals usd_amount exactly (the beneficiary receives usd_amount minus fees). This lets the account be drained to zero: pass the account's full available cash as usd_amount. The request is rejected if usd_amount is less than or equal to the fees. Defaults to false (fees added on top of usd_amount).