Top off at 12 VDC and time to 30 minutes.
The time is the easy one, the engine should run long enough to get every part hot to running temperature, we need to make sure no condensation or other issues, so a 30 minute run minimum time is a good number.
Depending on the loading of the generator a "cool down" may be included here, if we assume the load will be less as the voltage rises then the generator will be operating in a lesser loaded state and acting as a cool down run.
The battery is dead at 10.5 vdc fully charged when the float voltage is 13.5 and the current is at 1% of capacity, a little difficult to control the generator based on this criteria.
So using 12 volts to signal the shut down process that allows the generator to run for another 30 minutes to insure minimum running requirements and possible cool down would allow additional charging of the battery with less risk of over-charging the battery.
But these are my guesses, one should verify the intent of the settings to insure what they relate to before making adjustments.
CC is open for buisness, they can be contacted for advise, or if the manufacturer of the controller is known they can be contacted.