Refund of wrongly paid tax: claims allowed after reclassification if correct tax is paid and time limits are met. Clarification treats 'subsequently held' as including taxpayer-initiated reclassification and officer-led reclassification; refunds are available if the taxpayer pays tax under the correct head and files within two years from payment under that head (or, for pre-amendment payments, within two years from the amendment's commencement). Pending or disposed applications are governed by the amended rule; refunds are not available where tax was adjusted by issuance of a credit note.