It will charge them fine, just a bit slower. Max is six amps per port, but if your using all four you likely wont get more than about five amps in the real world.To put out big power you really need a dc charger with a really big separate power supply.
I looked into it before I picked up the X4 but even for a single port charger and power supply that would charge the big five and six cell batteries at max speed was going to be around five or six hundred dollars Canadian. My X4 was two hundred and twenty five and it although it chargers at a slower rate it does charge four at a time and will do up to six cell.