One of my colleague Sudip Tola prepared a documentation and training session.
Let me take it with an example where you can understand easily. Maruti is selling cars in different colors. When a dealer orders for 50 cars. he randomly says 30 in white and 10 in blue and 10 in red.
However during despatches , the user finds available qty is vary from ordered coloured.
Here the functionality helps in selecting the colors during deliveries. [ This is morethan lot system - do not confuse with lots].
Still i do not come across - if any one uses in real scenario.