In the book it says delay cost reflects the price difference due to delay in filling the order. The example in the book calculates it as (700/1000)* [(10.05-100/10]. I don’t get why they used 10.05 instead of 10.07; when 10.07 is the price at which the trade was eventually executed.
You will always look at the closing price of the market in the previous day. This is given in the paragraph above where the four components are being analyzed. This is due to non-execution on the day the trade was entered.