IWR6843AOP: Conducted power of multiple antenna for FCC certification

What is the affect on conducted power of running multiple antennae at once? I see from swra753.pdf that 10*log(N) is added to the overall gain (and thus, radiated power), but why does this not have an affect on conducted power as well?

FCC specifies a peak conducted power of -10 dBm for high-bandwidth applications, so I am setting txOutPowerBackoff to 0x181818 to bring power of each antenna from 12 dBm to -12 dBm. I calculate radiated power with three active antenna as the following:

P-conducted + Gain + 10*log(N) = -12 + 5.2 + 10*log(3) = -2.03 dBm

Does this seem correct? If three antenna operate at the same time, will conducted power still only be -12 dBm?

Thanks!