STEVAL-MKBOXPRO BLUENRG-LP Transmit Power cannot be changed ... in practice

Hi,

i experimented the following configuration STEVAL-MKBOXPRO with BLEMLC code available within FP-SNS-STBOX1 package. For my specific application, i want to increase the BLE transmit power of the BlueNRG-LP chip of the MKBOXPRO. So i modified the code with the aci_hal_set_tx_power_level(1,31) +8dBm (since default value was  aci_hal_set_tx_power_level(1,4) -16dBm). Everything is fine with compilation with Cube IDE.

But in practice with the app ST BLE Sensor v5.2.6, the real connection distance still remains about 25m, with a disconnect when RSSI is about -92dBm. These values are correct but what is not correct is that any tries to change aci_hal_set_tx_power_level with different "theoretical" power levels (from -54dBm to +8dBm) do not change anything in practice. It looks like aci_hal_set_tx_power_level has no effect on "real" transmitted poser.

Any help will be welcomed to this topic.

Thanks reading et thanks in advance or your help. Christian