Time of Supply: interest or penal charges taxed when received, at primary supply rate; invoice timing governs liability. Additions to the value of a goods supply by way of interest, late fee or penalty are taxable on the date the supplier receives such amounts; these additions form part of the taxable value of the primary supply and are charged at the HSN and rate applicable to that primary supply. Invoice issuance deadlines for goods (movement, non movement, continuous supplies, approval sales) govern the timing of liability. Penal or additional interest charged by a third party lender may be excluded from the supplier's taxable value where an exemption notification applies.