Sure, the bar of 'fully understanding' is ridiculous. People don't have 100% accuracy with anything. Most people would also fail the same measure if the document was spoken vs written so despite the name it has little to do with literacy.
Note: The bar for functional literacy includes banking paperwork which is intentionally designed to be confusing. If more people understood it they would rewrite it to be less clear. Also, your failure to understand what you linked precludes you from the ranks of 'functional literacy'.
PS: While high, you might reasonably interpret at least intermediate as an acceptable level for college graduates and that's well over 80%.
Note: The bar for functional literacy includes banking paperwork which is intentionally designed to be confusing. If more people understood it they would rewrite it to be less clear. Also, your failure to understand what you linked precludes you from the ranks of 'functional literacy'.
PS: While high, you might reasonably interpret at least intermediate as an acceptable level for college graduates and that's well over 80%.