Restrict unknown IP on trusted MAC explanation

Is it just me or is the Sophos XG manual poorly written?

I have a long list of errata's I've been making in general but to me it doesn't seem to aim itself at either a novice network or network professional.

Example. Page 120 DoS & spoof protection

It mentions the 'Restrict unknown IP on trusted MAC' option which drops packets which have a unknown IP for a known MAC address. Now isn't this the same things as the IP-MAC filter ?? Why have both options what is the difference ?? Is this a redundant check box as this provides the same function?

Then we have IP spoofing which states: If the source IP address of a packet does not match any entry on the firewall's routing table etc the packet is dropped ?? Well surely it will match any entry on most firewall routing tables due to the 0.0.0.0 route which is naturally added ?

Please point out where I'm misunderstanding this ?

Thanks

Ed