According to § 25 Inheritance and Gift Tax Act (old version) the deferred tax can be discharged with its net present value according to § 12 para. 3 Valuation Act by the acquirer on request at any time. The decisive period is calculated based on the relevant statistical remaining life expectancy of the person concerned.
Excursus
According to § 25 IGTA which was applied to valuation dates before January 1, 2009, the acquisition of assets of which uses the donor or the spouse of the deceased (donor) was entitled to or which were burdened with an obligation of recurring services in favour of these persons, was taxed without considering these uses/services. The tax which was attributed to these obligations was to be deferred until their expiration. The deferred tax could be discharged with its net present value according to § 12 para. 3 Valuation Act by the acquirer on request at any time. In practice, the tax was usually discharged immediately since the net present value was calculated based on an interest rate of 5.5%.