Rate Valid From/To Date

What is the Rate date? How is it determined?

1. The “Rate Date” field of the Supplier Product (eg. Uplift,Delivery,Pack,Unpack,Carton Deliver): if the rate date is set and not blank, this will take precedence.  
   
   

2. If the above is blank, it will then use the date that the invoice/cost line is created, provided the system parameter “UseTodayForCostOptionDate: Use Today For Cost Option Date” is set to Y.
   
   

3. If the above parameter is not set to Y, it will use the Cost Option Date (the date the cost option is generated, which displays on the bottom left of the screen)