anchor.diff:  		{ok, AcctSessionId} = radius_attributes:find(?AcctSessionId, Attributes),
   		ok = disk_log:log(Log, Attributes),
   		NewState = case decrement_balance(Subscriber, Usage) of
  -			{ok, OverUsed} when OverUsed =< 0 ->
  +			{ok, OverUsed, false} when OverUsed =< 0 ->
   				case supervisor:start_child(DiscSup, [[Address, NasID,
   						Subscriber, AcctSessionId, Secret, Attributes, DiskId], [{debug, [trace]}]]) of
   					{ok, _Child} ->
  
positive.code: 							{error, Reason}]),
  						State
  				end;
  			{ok, _SufficientBalance} ->
  				State
  		end,
  		{reply, {ok, response(Id, Authenticator, Secret)}, NewState}
  
negative.code: 
  -spec decrement_balance(Subscriber :: string() | binary(),
  		Usage :: non_neg_integer()) ->
  	{ok, NewBalance :: integer(), DiscFlag :: boolean()}|
  			{error, Reason :: not_found | term()}.
  %% @doc Decrements subscriber's current balance
  decrement_balance(Subscriber, Usage) when is_list(Subscriber) ->
  	decrement_balance(list_to_binary(Subscriber), Usage);
  