Smart modes in mods choose the suggested wattage for THEIR range of coils. All it does is check the resistance and limit the wattage - in this case for the Voopoo range of coils. The mod has no idea what the coil is, it only reads the resistance so it is only 'Smart' when you use the range of coils and tank that were included in the full kit version of that particular mod - for everything else it is really thick and can't be trusted.
If you use any other tank or coils from another manufacturer then you would be better off using RBA mode and start at the lowest suggested wattage, gradually increasing power if you need to, but not going above the recommended max rating for that coil.