KFLF is a prior injection correction map and not a lambda map. You can increase by 10% the KFLF but your fuel will be the same as lambda request.
If you change the values in KFLF your air/fuel mixture will change, you may not see the change (if logging with wideband) if it is small and your in close loop lambda control since the ECU will compensate (up to a given level) but you will see changes in the fuel trims. I've tested this multiple times.