FS Difference between A2D and D2A on the AD9371


As i understand the 0dBFS of the A2D = -14dBm@CW and the 0dBFS of the D2A= +6dBm. if i want to connect A2D to D2A is the FS difference will be 20dB?

It means , that i need to sample the -14dBm and before i am sending the data i will have to increase it (in the FPGA so it will fit to the D2A FS (by 20dB)?

Please provide some explanation and calculation to the FS difference between A2D and D2A and how it will affect the system