In absence of the actual specs, we can calculate a theoretical maximum and know that the actual performance will be at least slightly less. The power supply is 5A x 12V = 60W. The USB ports will be 5V, so neglecting conversion losses, we would have at most 60W / 5V = 12A total to divide among the ports. So 12A / 13 USB 3.0 ports = 0.9A maximum. If the last port is being used, and it really guarantees 2.4A as stated, that would leave a theoretical max for the other 13 ports of (12A - 2.4A) / 13 = 0.7A per port. (The actual numbers will at least be slightly less.)