Input tax credit and customs duty credit rules revised to restrict carried forward credit and mandate electronic declarations for eligibility. Amendments to the Assam GST Rules revise procedural timeframes and require electronic declaration in FORM GST ITC-01 for input tax credit eligibility; add rule 44A limiting Central tax credit carried forward from additional customs duty on imported gold dore bar to one-sixth and prescribing debit of the remaining five-sixth at the time of supply or within the transition period; modify forms and payment procedures including TRAN-1, REG-01 and payment challan validity; and require appointment of officers of Joint Commissioner rank to the Authority for Advance Ruling.