SAM's reports are not customizable because creating or modifying a report template requires knowledge of a scripting language and of SAM's internal variable names that we do not expect most people to have.
If there is something you would like us to add to a report, please let me know, and we will consider modifying the template.
By the way, there is an error in the PVWatts report template that we've temporarily addressed as described in this forum thread:
PVWatts report issue with rated capacity
Best regards,
Paul.