No barf at all.
Remember, she doesn’t have to agree to be “interviewed” (in reality, questioned as the principal suspect in a federal felony matter) at all. She has Miranda rights.... but of course, if she exercises them, it’s bad juju for her.
When the report is finally issued, this way, no one will be able to say they did not give Hillary “every consideration”
This takes away some of her “their picking on me” whining.
That's what I was thinking - I hope you're right. They are avoiding missteps like the plague so the charges can't be diluted or obfuscated.