Systems and methods are provided for executing a plurality of money transfers, at least one term of which is dependent on the value of a fluctuating parameter, for example a currency exchange rate or the amount of a transaction service fee. The customer may stage a first money transfer at a money-transfer system and a first value of the fluctuating parameter may be determined by a host processor. The first money transfer may then be executed by the money-transfer system using the first value of the fluctuating parameter and a unique lock-in value identifier may be stored in the host processor's memory that associates the first value of the fluctuating parameter with the customer.