Any item that reads 'XYZ Elemental "Magic Atk. Bonus" +' (sometimes it reads just 'XYZ Elemental +' or 'XYZ Magic Attack +') is not added to your existing MAB, but, also, it's not affinity itself.
Instead, what happens is that on the DMG=mDMG(total)x(MAB/MDB)xMultiplier formula, instead of adding MAB to the regular factor that's divided by MDB, instead, pieces that are elemental related end up being finalDMG=DMGx1(elementMAB/100) for the related element.
You can test this with Kaikias Cape (4 elementMAB) out-damaging Toro Cape (10 MAB) on Wind based spells or Quanpur Necklace (7 MAB 5 elementMAB) out-damaging Eddy Necklace (11 MAB) for more than it ought to, if it were regular MAB.
Lastly, this is also darn good for 1.28 DMG Comets (along with Xsaeta I and macc+ gear and/or potions).
@Jubehnka it is additive with the affinity DMG+ term, so it is just affinity dmg renamed.
Which is easier to understand?
[Element: Dark] Affinity: Magic Damage+4.6
Dark Elemental "Magic Atk. Bonus"+28
They did similar with Occ. quickens spellcasting by later using Quick Cast to identify the same term.
I don't know whether lv.51 staves are the exact same term as https://www.bg-wiki.com/bg/Trial_884 "affinity" however it was found out with abyssea atmas that affinity: mdmg & atma are additive however atma+lv.51 staff are multiplicative. When I first did testing on this piece of gear I also found it to be additive with the TotM staff I already finished to the lv.99 version which means it is just a renamed version of the same term.
this item doesn't directly impact the potency of drain and aspir as neither spell directly causes damage in the traditional ffxi sense.
drain/aspir potency gear is the exception and unless this item has a hidden trait for that, it's not so important for a drain aspir set. getting a solid augment on resin gear with both drain/aspir potency and magic accuracy would be a better time investment then this piece. also, anything that has those 2 stats as well as dark magic skill would be the ideal piece for this spell line.
Archon Ring from ADL has Dark Element: MAB on it and it, and as far as I have seen, does not increase Drain/Aspir returns. This MIGHT fall under the same category.
However, I have also read that the Ice Element: Magic Attack Bonus +15 on Ngqoqwanb seems to register as Ice Affinity.
Testing needs to be done, as always, instead of assumptions being thrown out.
