CG76708 - Wasting assets: introduction: additional expenditure

A person who owns a wasting asset may incur additional expenditure which enhances the value of the asset. This will not affect the predictable life of the asset but may alter its scrap or residual value.

If additional expenditure does affect the scrap or residual value, then you adjust this on the basis that the expenditure was incurred when the asset was originally acquired, not when it was actually incurred.