This oscillator for the Elliott Theory has been invented by Tom Joseph and it's useful to correctly count the impulsive and corrective waves.
Its difference compared to a simple MACD is the peculiarity to use the ratio between the Fast SMA (default period set to 5) and the Slow SMA (default period se to 35).
The used formula is as below: ( (fast_SMA / slow_SMA) -1 ) * 100