Mirror statistics of export and import between counterparty countries reveals the problems leading to discrepancies in the official information on the tradestructure. In the article the main results of the comparative analysis of the size of the customs duty rate in relation to "problem" goods, which were found in reporting of import of Norway from Russia in Norwegian data, are presented. The characteristics and distinctive features of customs tariff used in Norway are given. The main conclusions and further directions of research are formulated.