Maybe it's possible to configure the ASUS bandwidth limiter manually? If you prefer not to use my script,
nvram set qos_enable=1
nvram set qos_type=2
nvram set qos_bw_rulelist="1>AA:BB:CC:DD:EE:FF>1024>256>0"
nvram commit
service restart_qos
service restart_firewall
WHERE:
qos_bw_rulelist =...