Specialized or Focuses ectra in slots and jutsu

Is there a difference between specializing in something and not specializing in something when it comes to slots and Jutsu's . As I have seen in some places where specializing in something is a "go" and gives a slightly higher bouns and in other places I have seen its not . Is this a typo or is that purposefully done ? Or are some slots ment to be general ( for the sake of balance purposes ) and some are ment to be specialized?