Porting Credit Card Tokens

We are investigating switching our credit card payment processor from Vantiv to PaymentExpress/FirstData.  Our Development department is concerned about recurring payments, having to obtain credit card numbers, and reentering the payments to obtain new tokens.  We are told by PX that there is a token migration service and they referred me to a Vantiv FAQ.  However, this service appears to be intended for porting tokens to Vantiv, not from.  Has anyone used the token migration service to move from Vantiv?  What are the costs?