Martin
Danke! Das englisch wird geschätzt.
My error must be in converting to the new kreuzer. It is not an exact 3 kr to 5 nkr conversion. So, rounding up at the old 9 kreuzer rates in the 1854 convention would give 16 new kreuzer. Suddenly it makes much more sense to me. It seems the 1862 agreement I have found is simply confirming the old convention as being back in force.
I believe the confusion began by looking at Austrian internal rates and seeing 9 kr converting to 15 nkr. At that point, I assumed that the same progression would follow with Sardinian (and the Kingdom of Italy) rates.
You patience and willingness to explain is appreciated.
Rob