This discussion clarifies the time limits for issuing supplementary invoices and debit notes under the GST Act. While supplementary invoices generally need to be issued within six months of the financial year's end, debit notes, which can include supplementary invoices for undercharged GST, do not have a specified time limit for issuance. The conversation also distinguishes between revised and supplementary invoices, noting that revised invoices have specific conditions related to registration dates, whereas supplementary invoices are used to correct deficiencies like uncollected GST.