I have no idea, and I despise it. USAA and eTrade both have TOTP, exclusively with the shitty, non-backup-able Symantec VIP app. Break your phone? You're boned! Symantec VIP on those sites don't provide 2FA verification (the thing where the phone asks to confirm the number on the client-side) and it doesn't provide push notifications.
It's literally a worse version of regular TOTP. And they're in the minority even having 2FA!
It's literally a worse version of regular TOTP. And they're in the minority even having 2FA!