I realize this could be a stupid question everyone knows the answer to...  my game is based more on virtual fighter than street fighter, so a lot of the terminology with the hits makes less sense to us.  "overhead" is a term for street fighter- a move created after street fighter two to hit players in the low block.  Virtual fighter has 3 levels of attacks- high, low , and medium or mid.  Mid level attacks, hit a low blocking opponent, but can be blocked with a high block.  "overhead" in UFE. 

What was left out of the terminology of UFE, is whether a "launcher" can be  from an "overhead" attack.  The way it is phrased now, a launcher can be blocked both low and high. Which means it has to be unblocked to connect.  Maybe this works for street fighter 2d games.  But for Tekken and Virtua Fighter games, this would never work.  The jump knee launcher is found in half the characters of virtual fighter.