This section provides 2 order-making powers to enable the Secretary of State to take account of the implications of varied Scottish rates of income tax for social security, child support, pension and war pension purposes.  They allow him, for those purposes, to determine whether a person is or is not to be treated as a Scottish taxpayer, and to specify what shall be treated as the Scottish rate of tax in any year of assessment.
The intention of the provisions is to ensure that benefit decisions can be made promptly without uncertainty over the appropriate tax rate to apply, where tax is relevant to benefit entitlement.  In the great majority of cases, the powers will have no effect on benefit entitlement.  They will reduce administrative costs which would otherwise arise, and prevent inconvenience to claimants both in Scotland and in the rest of the UK.
Commentary Part V: Miscellaneous and General Purpose and Effect