PAC file for Cisco proxy

I am trying to figure out why this pac file configuration is not working and its driving me nuts. It's very straight forward -

function FindProxyForURL(url, host) { if (isInNet(myIPaddress(), "192.168.1.0", "255.255.255.0")) return "PROXY 192.168.1.1:80"; else return "DIRECT"; }

However if I use the configuration below it works without any issues -

function FindProxyForURL(url, host) { return "PROXY 192.168.1.1:80"; }

Anyone have any ideas?