CC1352P: Why 15.4 stack channel 26 max power is 15dbm

Hi, TI Team

  The SDK is simplelink_cc13x2_26x2_sdk_5_20_00_52  example rtos\CC1352P_2_LAUNCHXL\ti154stack\collector_2_4g

   I found the maximum power of channel 26 is 5dbm lower than that of other channels.

   Why is the maximum power of channel 26 deliberately reduced?

/******************************************************************************
 * GLOBAL VARIABLES
 */
int8_t PLTableIeee[RF_CONFIG_IEEE_PL_NO_CHANNELS] =
{
     20,    //20dBm max for Channel = 11
     20,    //20dBm max for Channel = 12
     20,    //20dBm max for Channel = 13
     20,    //20dBm max for Channel = 14
     20,    //20dBm max for Channel = 15
     20,    //20dBm max for Channel = 16
     20,    //20dBm max for Channel = 17
     20,    //20dBm max for Channel = 18
     20,    //20dBm max for Channel = 19
     20,    //20dBm max for Channel = 20
     20,    //20dBm max for Channel = 21
     20,    //20dBm max for Channel = 22
     20,    //20dBm max for Channel = 23
     20,    //20dBm max for Channel = 24
     19,    //19dBm max for Channel = 25
     15,    //15dBm max for Channel = 26
};

macRfCfg_maxPower_t maxPowerIeee =
{
    RF_CONFIG_IEEE_PL_FIRST_CHANNEL,
    RF_CONFIG_IEEE_PL_NO_CHANNELS,
    PLTableIeee
};

Regards,
LiuMengyang