No, it doesn't affect other VPN settings such as "Advertised networks".
The advertised network must be your LAN subnet AND this subnet MUST be different from the VPN subnet you choose.
For instance, if your LAN is 192.168.0.0/24, then your VPN network must be different, for example 192.168.1.0/24.
If you use NAT with one NIC, VPN server will be the proxy for VPN clients within the advertised networks. If you don't use NAT, then all the hosts within the advertised networks must know how to reach eBox.
I hope this clarifies a little.