I understood that the assets are valued with reference to the...

I understood that the assets are valued with reference to the NPV, not on a cost basis. The accretion of the discount should increase the value of each remaining cash flow 4-5% per annum if the timing of the expected remaining cashflow is unchanged. However, clearly the cashflows have been kicked down the road, so each cashflow should be discounted further and be worth less (price, volume and costs remaining equal). The valuation of these assets are not going to be determined by management's forecasts, but management will be using these calculations to justify capital/funding strategies.

NPV/DCF look simple, but have many embedded assumptions, I doubt an auditor would look into these - they just want the piece of paper to tick the box. Usually when auditors do start querying the assumptions with any rigor - it is rigor mortis, as it is almost always an autopsy.

My suspicion is that the auditors just woke up...