nphy tx_gain_epa and rf_pwr_offset

Are the nphy rev 2057 ntab_tx_gain_epa and ntab_rf_pwr_offset serving
the same purpose or the epa are a better have?
I could notice that ntab_tx_gain_ipa is always present but not epa.
And what's the purpose of those two?
What is the missing for the full support of nphy rev2057 rev9 and rev14.
I think I would be able to provide them, if I know what's lacking
(i.e., any tables or logics etc.).