If you have OC Sheriff sign it off they will charge you a service fee to get it signed off.
CHP will simply sign it off for you and no fee added. You might get lucky on the street by a Deputy but most will now tell you to head over to a department because Deputies are no longer allowed to sign them off.
damnn..last time i got a "No Plate" ticket..i got pulled over a CHP
well i went to go pay it off..they made me pay 20 bucks at the police station and get it signed off..but right after they made me go to the court house..and made me pay another 25 bucks cuz it was a CHP that pulled me over..so i had to pay a total of 45 bucks just for a fix-it-ticket...
i dunno if this helps..but just throwing in my experience