Where an asset's carrying amount based on its cost is written down to its recoverable amount, AASB 136 specifies that:

		since this constitutes a revaluation of the asset, all assets in that class must be revalued.
		the amount written down is to be treated as an adjustment to the revaluation surplus.
		the write-down is not considered to be a revaluation, so the entity is not obliged to revalue that whole class of non-current assets.
		to the extent that the asset was revalued upward in the past, the amount of the write-off may be transferred to the revaluation surplus and any remaining amount should be expensed.