How can an Asset Store publisher verify the number of licenses sold?

The Unity Asset Store publisher administration page gives publishers the option to “Verify Invoice”. But there doesn’t seem to be a way to see the number of licenses purchased for a given invoice. Is there a way to verify the quantity of licenses purchased in a particular order? Can there be multiple licenses associated with one invoice number, or is there always one license per invoice number?

this seems to be a question for : assetstore@unity3d.com

I recently noticed the asset store is finally giving this information. Quantity is one of the json properties here:

http://api.assetstore.unity3d.com/api-docs/#!/invoice