But it means that the app will work without changing the DHCP reservation, and not be dependent on ANY IP address.
Both of those things would be true if you just did it once when the client starts though :S
Perhaps you dont understand what I am suggesting - what I am suggesting is that instead of the server constantly broadcasting, the client just broadcasts when it needs to locate the server and when the server receives this broadcasted message it replies to the client that sent it to let it know what IP address the server currently has.

I also dont understand how 8640 packets is "just noise" but a couple of packets from a ping is a huge waste...