I guess you're used to standard billions (a million millions). A US billion would certainly suffer from losing hundreds of millions, you're talking about a double-digit percent.
If someone is writing English and puts "billion" for 10^12, that's a translation error, much like writing "my grandfather became pregnant when he realized he'd locked the keys inside the car." (Instead of "embarrassed.")
Conversely, if I wrote a French or German sentence and put "billion" for 10^9, then I'd be the one making the translation mistake.
https://www.etymonline.com/word/billion
I would vote to revert it.