I'm assuming you are discharging a 2s pack. If so you are running into the discharge wattage limit (130 watts). 8 volts x 18 amps roughly equals 130 watts.

The 4010Duo has a feature where you can hook up an external load to one of the channels and use it to discharge from the other channel. Doing this you can discharge up to 40 amps and 1600 watts. Look at the battery forum over at RC Groups for various discharge devices. People use light bulbs, resistors, etc. Main thing to remember is you need to cool the external load with a proper heat sink and/or fan.

As for cycling I know the charger does it. Not sure what stats it keeps. Also, I don't know when using the external discharge described above if the charger keeps the discharge current constant like a Turbo 30 would do. Perhaps someone else in this forum could provide insight.