comp_sci_kid

eh?

if an asset has a market to determine fair value, just use fair value and ignore cash flows.

if there is no market/mechanism to know fair value, approximate it via cash flows to determine impairment.

it doesn't make sense to write-down based on cash flows if the fair value is higher, since, if liquidated, you could just sell the asset for (near and net to) fair value. it's not really impaired at that point.