In a long position the gains are "automatically" reinvested since the initial sum and the gains are on the market. With a short position this is no more true.
This CloseStrategy tries to defeat this by reinvesting the gains each time a certain amount of gain has been made since last time the position was augmented.
Use this CloseStrategy at the end of the "system chain" so that a position is not augmented if it's planned to be closed.