Many franchises require stock aging on ex-demonstrator stock to start aging from zero on the day that the vehicle is no longer a demonstrator.
For example, a vehicle may have been a Demonstrator for 6 months, but then is transferred back to saleable stock and sold a week later. The vehicle has been in stock for 6 months and one week, but for reporting purposes it is desired to show the vehicle as selling after one week.
The way to achieve this is to update the date in stock on the stock record immediately after transferring back from a Demonstrator vehicle into saleable stock. This will start the ageing count from zero again.