It doesn't seem to include the subvocal folds in the model. Which is what you buzz when throat singing.
I figured out how to use my subvocal folds voluntarily. It's added a lot of gravitas to my groans and huffy protestations at work.
I also use it when saying "uh". To catch people off guard. They don't expect me to sound like Johnny Cash when I'm straining for an answer.