Multilateral netting

Firstly, you are reading too much into things. If I owe you $100 and you owe me $20, then if we net off I pay you $80. Where the $80 I pay you comes from is irrelevant (presumably I have the cash). The importance of netting when there are different currencies involved is simply to cut down on the number of transactions and therefore save transaction costs and reduce the exchange rate risk. MJY and Multidrop were set by different examiners, which is why the answers are set out differently. However the end result in the same in both cases and it doesn't matter which way you set it out.