I want to know the answer to the following question:
When was ISO/IEC 646 published?
All the background I'm provided with is that "However, the four years that elapsed between the publication of ASCII-1963 and ISO's first acceptance of an international recommendation during 1967 caused ASCII's choices for the national use characters to seem to be de facto standards for the world, causing confusion and incompatibility once other countries did begin to make their own assignments to these code points.". Is that enough to answer the question?
Answer: no