Thanks for that. Actually my figure were sales revenue figures...

Thanks for that. Actually my figure were sales revenue figures rather than profit, but thanks all the same as your thoughts fill a few gaps for me. I am not sure, but NST may be incurring some lease commitments similar to BDR - I presume if NST does have lease commitments that they would be treated for accounting puposes on a similar basis by both companies. It can also be expected that as equipment leases expire the respective equipment is replaced and new leases entered into, so I would expect there will always be an ongoing lease commitment component in the AISC (for both companies). Also AISC for NST should be lower than A$1075 (as used in your calculations above) - they are targetting an average of
The POG is a big factor for both companies as when POG drops it is a direct cut into their respective profit margins. The objective for both companies is (or should be) to keep working at reducing AISC (something over which they have some control) as they have no control over POG. The healthier the profit margin (the bigger the buffer the better) the better positioned they are to ride out any dips in the POG.

Thanks again for your comments.