I'd be interested to see if you can make this work without the static routes. Of the face of it they make no sense from the Asus' perspective. Just like accessing a cable modem on 192.168.100.1 a static route isn't usually necessary because the default gateway will send traffic to the WAN anyway. The only time I can think a static route would be required is if you're using the VPN client on the router, which changes the default gateway. As for the route for 192.168.100.24, that makes no sense at all.