In the push classless route part the script removes zeros from the router bytes. This is not the desired behavior.
For example this

static-route {
    destination-subnet "172.22.128.0/17"
    router "172.22.0.12"
}

will create this in the dhcpd.conf:

option rfc3442-static-route 17,172,22,128,172,22,12;
option windows-static-route 17,172,22,128,172,22,12;

The zero disappeared in the router address. The desired output would be:

option rfc3442-static-route 17,172,22,128,172,22,0,12;
option windows-static-route 17,172,22,128,172,22,0,12;

(ISC.org is currently unavailable so I cannot link any official documentation)