Because there is no Fifth Amendment Privilege against self-incrimination at a California DMV hearing, your DMV attorney usually will not want you to be present at the hearing. Why not? The Driver Safety Officer can unfortunately call you as a witness and have you to testify against yourself if you show. And they're trained to discredit you and instructed to develop inconsistencies.
Guess what? There's no independent DUI judge to offer some protection, you are strongly advised not to try to represent yourself.
A DUI attorney has just 10 CALENDAR DAYS after the DUI arrest to call the California DMV Driver Safety Office to timely demand a hearing. You waive your right to a hearing if the 10 day deadline expires.