Duration datatype and truncation

Greetings!

For the duration datatype, does number:truncate-on-overflow define
truncation for all occurrences of that datatype? 

I ran into a situation today where I put in a cross-reference this
attribute and then it occurred to me to ask if it is general to all
occurrences of the duration datatype?

Thanks!

Hope everyone is having a great week!

Patrick