LTE Modem Signal LEDs

I want to be able to shoe the modem signal with the 5 LEDs on the RB411 (as I do with a a 3g modem MC8790)
but all the leds are light on even when the signal is low .
why is it?

Flags: X - disabled, * - default 
 #    TYPE                     INTERFACE                  LEDS                 
 0    modem-signal             lte1                       led1                 
 1    modem-signal             lte1                       led2                 
 2    modem-signal             lte1                       led3                 
 3    modem-signal             lte1                       led4                 
 4    modem-signal             lte1                       led



status: call in progress
         pin-status: no password required
      functionality: full
       manufacturer: Sierra Wireless, Incorporated
              model: MC7700
           revision: SWI9200X_03.05.20.05ap r5847 carmd-en-10527 2013/06/21 17:02:10
      signal-strengh: -73 dBm

?

Thanks ,

hi there,

What is the secret configure LEDs for LTE modem signal? My LEDs are does not want show signal strength. Is there any example?