Update hooks and features_revert
It is my understanding that the update hook only runs once per update. The function is hook_update_n where 'N' is the instance of the update hook. Each time you want to revert your feature upon a code update you need a new update hook. This is why if you increase the number it works. If you are increasing your version numbers when you regenerate your feature, and also reverting your feature in code with an update hook, those numbers should match, and you will have an update hook for every version increment. 

Source: Drupal API.