BEC and SITC difference for total export single year

[V.Korovin]

Dear Community,

I was trying to download information on the US and Norway total gross exports in 2017 using BEC and SITC2 classification. 

Surprisingly I received two different outcomes at the highest aggregation level (see attachments).

I was checking the nomenclature concordance and could not find omitted sectors. Did I overlook something? Making the same query at https://comtrade.un.org/data/, I did not receive this discrepancy.

 

Could you please explain what is the source of this difference in WITS?

With kind regards,

Vladimir