8. Determination of point of taxation in case of copyrights, etc. .- 

In respect of royalties and payments pertaining to copyrights, trademarks, designs or patents, where the whole amount of the consideration for the provision of service is not ascertainable at the time when service was performed, and subsequently the use or the benefit of these services by a person other than the provider gives rise to any payment of consideration, the service shall be treated as having been provided each time when a payment in respect of such use or the benefit is received by the provider in respect thereof, or an invoice is issued by the provider, whichever is earlier.