Print Credit For A Specific Buy All Instant Download Resolution

I'd like to be able to provide clients with a Print Credit code that would allow them essentially to do Buy All for Instant Downloads for everything from their session at a specific resolution. 

Is there a way to do this? I think Print Credits only work with Collections. So, is there a way to include a Buy All option into a Collection that would allow this to work? 

There is not a way to do a print credit for a buy all. 

If your buy alls are a set price you could issue a coupon for that amount.

You could also assign them free downloads to the gallery. (Assign a Customer or Customers To Download For Free On A Per Gallery Basis)