Advanced Custom Fields Plugin will enable you to use unlimited custom fields and field groups with WordPress Download Manager. You can create different custom field groups a per your package needs. This Add-on will be helpful for you if you want to show additional package information in a formatted way. Also, you can use this add-on to extend email lock feature, when need to capture additional data from site visitors.
Advanced Custom Fields Add-on Features:
Create Unlimited Field Groups
Create Unlimited Fields
Easy to use form field generator
Optional/Required form field
6 Different Field Type Support
Auto generate template tag and PHP code snippet
Add additional fields with user registation form
Customize front-end package form
Add Custom Field with Email Lock Form, you can capture additional information from user before download package
Export custom data captured with email lock
Custom field groups support, in case you need to collect different type info information from users for different downloads.