We implemented a web service that gets called on save. Can we get Form Builder to send all files uploaded in the form every time the form is saved, instead of just the files that were newly uploaded since the last time the form was saved?
I imagine you're implementing the persistence API. Assuming this is the case, the short answer is no.
But then, why would you want that to happen? If a file has already been saved to your persistence layer, when the data is saved you get the form definition with a "link" to that saved file. If you need to retrieve it, you can do so, but, unless I misunderstand what you're doing, you don't need to get it back from Form Builder.