[JBookTrader] Why does JBT use the different Position Sizing in differemt modes?

[just4look]

In PortfolioManager, there is code

public int getSize(Strategy strategy) {
Mode mode = dispatcher.getMode();
if (mode == Mode.BackTest || mode == Mode.Optimization) {
return 1;
}
int maxOpenPositions = strategy.getMaxOpenPositions();

..........

Why does JBT use the different Position Sizing in differemt modes?

Thanks