I do not understand.
Are you saying you can change the IP yourself on your flow modem???
Or do you mean you go into your router and manually create an IP configuration for the outside interface there instead of using the DHCP option?
I've had high latency issues in LoL in the past, which was fixed with a patch....but then reintroduced with yet another patch.
The work around has been to start the game, unplug your connection and plug it back in. (sounds crazy but it works)
not a svelte solution....so I wouldn't mind trying this for a more permanent fix.