This article explains how to use the Written Down Book Value and Written Down Tax Value columns within the Fixed Assets spread sheet.
After claiming 50% of the value of the asset in one year the sum of any allowance made in future years should only ever add up to the other 50%.
This is achieved by populating the remaining unclaimed value in column O.
As the asset is unlikely to depreciate by 50% the book value get's out of sync with the tax value.
Example: Asset originally purchased for £1000 Total allowance claimed so far £500 Actual depreciation £100