Mikrotik R52nM TX power isuue

Hello everybody,i noticed one thing about this card:i am using this card on 5 Ghz backbone link with Nv2,with default Tx power,but the Tx power value is not same than in the card of pdf,Mikrotik says that:

802.11n 5 Ghz:

MCS7 40 Mhz:13 dBm Tx power

But in the winbox show me only 10 dBm Tx power for MCS7 40 MHz

Because sometimes need +3 dBm Tx power

This is ok that’s way?

one chain is 10dbm, two chains 13dbm

I did not know this,yes at the moment i use only one chain with grid antennas,thank you for your reply