For me sometimes it just ran off. Starting I tot its an updated avg. price (either according to the market or the stats)
Then i figure it should be the cost price. But then again, my cost price should not be fluctuating (since I am in control of my whole process flow). Hence I tot its back to (above). Of coz its arguable (I produce Gas) that I buy power, hence, the cost might follow the price of my power (stated in the warehouse). But that brings up another issue.
When I start buying power (which the only thing i buy) i notice it takes the average price I bought it with, then again i was proven wrong as at one time, it shows the price I bought it with (this I double check it already and its not the average price).
Interesting.. so I never bother with that figure and i just go ahead and calculate my own cost price
