For a network, as used by IPAM, we care if *any* address in the range could possibly conflict with an existing address routed by the host. When given a single address, we only care if *that specific address* conflicts with an existing route.
For a network, as used by IPAM, we care if *any* address in the range could possibly conflict with an existing address routed by the host. When given a single address, we only care if *that specific address* conflicts with an existing route.