Apps that use UPS pricing but don't charge for labels

[EICstore]

Are there any apps that will charge your customers the current UPS rates, but will not automatically charge me/print a label? We are using a 3rd party for fulfillment that uses their own UPS account, but we can't integrate their rates through their app, and my customers are getting charged a lot less for shipping than we are getting charged by the fulfillment service.