LAHORE, Oct 3: The government has ordered a probe into heavy under-invoicing in import of paper and paper-board, resulting in colossal losses to the national exchequer. A valuation alert issued by the CBR to all collectors of Customs on Sept 29 called for strict vigilance of unscrupulous commercial importers as prime quality imported paper had been cleared as waste paper in at least nine cases. The Valuation and Post-Clearance Audit offices at Karachi and Lahore were also ordered to launch a thorough investigation into the matter and recover the evaded amount of taxes and duties.