Ex ante means "before the fact" and ex post means "after the fact."

Assume you are a damages expert hired as I was to calculate damages from a breach of contract case. The facts were that the defendant had breached a contract by not selling the plaintiff's product but had, instead, sold an inferior but cheaper product. The defendant had developed forecasts of the sales of plaintiff's products before the breach. These sales were not made, but were forecasted for 2010 - 2012. The defendant's actual sales of the cheaper, inferior product in 2010 - 2012 were lower than the forecasted sales of the plaintiff's product. If you were calculating benefit of the bargain damages, which sales would you use in your estimate of the total damages -- actual or forecasted?