AASB 1 First-time Adoption of Australian Accounting Standards D21-D21A: Decommissioning liabilities in the cost of property, plant and equipment: instead of applying Interpretation 1 to pre-transition changes, measure the liability at the transition date under AASB 137, discount it back to the obligation date to find the amount in the asset's cost, and compute the depreciation to date; oil and gas assets under the allocation relief measure the liability at transition with the difference to equity

What does D21-D21A require?

Pre-transition changes in a decommissioning, restoration or comparable liability need not be tracked through the asset under Interpretation 1. Instead the entity measures the liability at the transition date under AASB 137, works out what the related asset's cost would have carried when the obligation first arose, by discounting that liability back to the origination date at its best estimate of the risk-adjusted rate that applied then, and calculates the accumulated depreciation on that amount at the transition date under its current policy. An entity using the oil and gas allocation relief for development or production assets measures the liability at the transition date and recognises the difference from the previous GAAP liability directly in retained earnings.