Field Sobriety Tests are VOLUNTARY!!
A simple google search will help you understand
And as I wrote, in California your license can be revoked, suspended by either the courts, or the DMV-administratively or both.
When you accept your license, you sign a binding legal contract, which states that if you refuse a sobriety test, your license can be revoked, administratively.
I already know this without google. Your citation regards the legal-court side of license loss.
Most DUI attorneys specialize, and would advise against sobriety testing. They get a case and $thousands of your money, and you get your license revoked administratively by the DMV.
But hey, why not go for it? If you are drunk, you will eventually lose the license BOTH ways.
I would expect the sentencing judge to be more harsh with those who refused the tests.