/added 22 Aug 2009
Postage due items from USA to Sweden
1 Jan 1966 to 31 Dec 1966
US foreign surface letter rate 11 c
Swedish foreign surface letter rate 60 öre
US handstamp shows amount to pay in US cents (normally double deficiency) and US surface letter rate.
In Sweden the indicated fraction multiplied by 60 and rounded up to nearest 5 öre was normally paid by affixing stamps on the item.

Air mail postcard with 7 cent. Correct rate 11 cent. Shortpaid 4 cent. US due handstamp indicates double deficiency 2x4=8 cent and foreign letter rate 11 cent. In Sweden 8/11 of foreign letter rate 60 öre = 43.64 öre rounded up to 45 öre. A correct label has been affixed, but by mistake only 40 öre as due.