A quick question about Arcane Thesis

[Sissyphus]

I'm Building a character who specializes in metmagicd fireballs, and i have a simple question.

Does the arcane thesis subtract one from the level of every meta magic feat (would it drop +1's to same levels) or just remove one added level total?

[kamikasei]

It can be read either way, but most naturally to my eyes it applies to each metamagic feat applied. That's good, but not too broken so long as you limit it to a minimum of +0 per feat. Where it's been abused is by combining high-cost metamagics with a bunch of +0 metamagics, so that the +0s become -1s and offset things like Quicken.

[PairO'Dice Lost]

Post-errata, the feat allows you to apply it once to each metamagic feat, even for a negative adjustment, as long as the final spell slot is no lower than the original, so with the fireball example you could cast an energy substituted (cold) (-1) silent (+1) fireball as a 3rd level spell, but an energy substituted (cold) fireball is still 3rd level.

[tyckspoon]

It applies to each metamagic feat; the errata adds an example that says so explicitly.

[RTGoodman]

Yes, it applies to each metamagic feat separately, but it can't be used to make the final spell level lower than the original. See the PHB2 errata.

Page 74– Arcane Thesis [Substitution]
Should read, “When you apply any metamagic feats
other than Heighten Spell” Thus if you were to
prepare an empowered maximized magic missile
(assuming magic missile is the spell you choose for
your Arcane Thesis), it would be prepared as a 4th
level spell (+1 level for empowered, down from +2;
and +2 levels for maximized, down from +3).

Page 74 – Arcane Thesis [Omission]
Add the following text to the end of the “Benefit”
section: “A spell cannot be reduced to below its
original level with the use of this feat.”

Nothing, as far as I can tell, prevents it from working with +0 adjustment Metamagic feats (to make them effectively -1 spell level), but that would be a good houserule to make for balance's sake.