The reason for the different labels on the device's 2 output ports is because the ports are wired differently.
As far as I understand it, the Apple port is not compliant with USB standards, and if you try to charge a compliant device such as an Android phone from this port, it will charge at 0.5A max. This is enough to slowly charge a switched off Android phone, but if the phone is on and drawing a large current such as when being used as a satnav, then the 0.5A supply probably won't be enough and the phone will slowly discharge. This is because the phone mistakenly thinks it's in USB mode and connected to a PC for data transfer, and the 0.5A limit is to protect the PC's USB port from being overloaded.
To trick the Android phone/USB compliant device into charging at full speed (up to it's maximum allowed or the 2.4A max of this charger, whichever is the smaller) if connected to the Apple output port, the right cable should be used. This will put it in AC mode rather than USB mode. Instead of using a normal USB cable which is fully wired for both charging and data transfer, you should instead use a cable which has the 2 central data pins connected together or disconnected. Such cables are often sold as a Fast Charging USB Cables and are not suitable for data transfer. They also need to have thicker copper conductors than normal cheap USB cables to allow for the higher current flows involved. PortaPow sell a few cables of different lengths on Amazon which sound suitable, though I haven't received mine yet to test them! You can also modify your existing cable if you know what you're doing.
Obviously, any normal USB cable can be used from the Android port (rather than the Apple port) to charge Android devices at full speed, as long as it is reasonably good quality and the copper wire is thick. Thinner copper will work, but the higher resistance to current flow will cause greater losses and the device may not charge so quickly.