We run a mobile food truck and we do several private events. This is where the owner of the event pays for everything that we provide during that event. We have used our POS during one of these events and with each order we did the typical order placed and just said they paid with cash (this is our way of tracking the total sale at the end of the event).  This also allows us to track what was sold at this event for "next time".  The owner then pays the balance of the event at the end and it is typically by card. 

My question is this...so that we do not loose our inventory control and balance of what was sold, is there way that we can use the POS to continue doing this but not show that we made double the money that day.  i.e. total sale $345 and paid balance of $225. This way it doesn't look like we made $570. 

Thanks