Question about California's AMT v.s. Federal AMT

Hello all, I'm preparing tax this year with TurboTax Premier and have to pay AMT for my federal tax due to ISO exercise. When I went to the AMT section in State Taxes (CA),  there was a question titled "Enter other incentive stock options" — If you excluded any California stock options (CQSO) proceeds from your income, enter the amount for alternative minimum tax purposes. 

 

This field was pre-filled with my ISO exercise information that I previously entered in the federal tax section. However, since I don't have any CQSO proceeds, I put "0" in this field instead. This change of data made me from having a large balance due for CA tax to getting a refund and not subject to CA's AMT anymore. 

This made me wonder if I can actually put 0 in this field. Maybe I misinterpret this question? Is it possible for an individual to pay a good amount of federal AMT but not CA's AMT? 

Much appreciated!