Problem of a node with a lot of children

Hi, i'm working with CC2430 and zstack 1.4.2.1.0.

I've got the following network configuration:

(nwk_globals.c)

    #elif ( STACK_PROFILE_ID == NETWORK_SPECIFIC )
    byte CskipRtrs[MAX_NODE_DEPTH+1] = {5,5,5,5,0};
    byte CskipChldrn[MAX_NODE_DEPTH+1] = {35,35,35,35,0};

(nwk_globals.h)

#elif ( STACK_PROFILE_ID == NETWORK_SPECIFIC )
// define your own stack profile settings
    #define MAX_NODE_DEPTH          4
    #define NWK_MODE            NWK_MODE_MESH
    #define SECURITY_MODE       SECURITY_RESIDENTIAL
#if   ( SECURE != 0  )
    #define USE_NWK_SECURITY    1   // true or false
    #define SECURITY_LEVEL      5
#else
    #define USE_NWK_SECURITY    0   // true or false
    #define SECURITY_LEVEL      0
#endif

.........

// Maximum number in tables
#if !defined( NWK_MAX_DEVICE_LIST )
  #define NWK_MAX_DEVICE_LIST     40 // Maximum number of devices in the
                                    // Assoc/Device list.
#endif

I have connected to a router: 30 children end device and 3 others routers.

This router assign a correct address to his 33 children, however, is capable of send messages to just 22 of the 30 end devices. This 22 end devices are the first 22 that established a connection with the router. I have to modify another parameter to solve this problem?, Someone knows why this is happening?.

Thanks.