Advanced search count is not working with contribution options

Tested in my 3.3.7 civicrm site and in the civicrm demo site (http://drupal.demo.civicrm.org/).

Here are the steps :

• go to advanced search
• choose Contribution Status = Completed
• keep Display Results As Contact

I get :

• 16 Contacts found (which correspond to the number of contributions)
• 14 contact listed

I set this as major because if you want to get statistics, it gives you false information.