BPP EXAM KIT 86 DUSTY COMPANY VS 87 SUM KXP COMPANY

sir in 86 dusty company sum due to the new inventory policy when calculating the total cost of inventory under bulk purchase we found out the increase in average inventory and multiplied it with the finance cost and added that additional finace cost to the total cost of inventory sir in 87 kxp company there is a similar situation a cmpany is considereding the cost of ordering inventory in bulk to avail the discount here in the solution when they have found out the e total cost of inventory under bulk purchase they haven't found out the additional finance although there is an increase in average inventory still they havent added the additional cost of finance to the total cost of inventory like in dusty company? DOUBT - why havent they added the cost of additional finance in case of kxp company 2) would mark be deducted if i did