I'm still waiting on another example in the Bible where the term "twelve tribes" means something other than the nation of Israel as a whole. There are dozens of references. Just give one. One. I'll wait.
Exodus 28:21, And the stones shall be with the names of the children of "Israel", which is the children of Jacob.
Gen 37:3, Now "Israel" (Jacob) loved Joseph more than all his children, because he was the son of his old age; and he made him a coat of many colours. Israel in this verse has reference to Jacob, not all 12 of his children, if so, it would read "and the nation of Israel loved Joseph more than all his children". Do you think that is how it should have been written?
More times, than not, when the scriptures talk about Israel, they are talking about Jacob.