payables mangement Early settlement discount (plot co 12/13 and zps co 6/11).

hello sir first of all thanks alot for the great help you are doing 🙂 .
dear sir i have a confusion here in the 1st question i.e (plot co 12/13) they are calculating trade payable after discount as 456000x1x0.99×30/365 but in next question(zps co 6/11) they are calculatingafter disount trade payables as 900000×30/365 my confusion is that why they are not taking into account of settlement discount of 0.5% in zps co but in plot co they did take into account.Iam reffering to the examiners answer. 🙂