Determining Bonus From GMW, MV

One of the players IMC has made the assertion that his 13th-level artificer (caster level 13) can cast GMW or MV and get a +4. His logic appears to be that the bonus increases by one per four levels. According to that approach it is +3 at 12, and +4 at 13. I have previously been simply dividing caster level by four, and not rounding up. It seems that his approach is basically equivalent to rounding up.

Which method is generally more in accord with the RAW?

srd said:

Magic Weapon, Greater
Transmutation
Level: Clr 4, Pal 3, Sor/Wiz 3
Components: V, S, M/DF
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One weapon or fifty projectiles (all of which must be in contact with each other at the time of casting)
Duration: 1 hour/level
Saving Throw: Will negates (harmless, object)
Spell Resistance: Yes (harmless, object)

This spell functions like magic weapon, except that it gives a weapon an enhancement bonus on attack and damage rolls of +1 per four caster levels (maximum +5).

Alternatively, you can affect as many as fifty arrows, bolts, or bullets. The projectiles must be of the same kind, and they have to be together (in the same quiver or other container). Projectiles, but not thrown weapons, lose their transmutation when used. (Treat shuriken as projectiles, rather than as thrown weapons, for the purpose of this spell.)

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It says it GIVES an enhancement bonus of +1 per four levels, and we all know enhancement bonuses don't stack. If it said it increases, that would be different.

So you are saying that RAW favors dividing by four (and not rounding up), the way I have previously adjucated it?

Thanks.

Shield of faith gives an example of how it works

+2 and an additional +1 per 6 caster levels to a maximum of +5 at 18th level. Round down

The close range description also rounds down

I have always understood these rules to imply complete sets or groups.

For example, Magic Missle say for every two levels beyond 1st you get an extra missle. Thus at the levels it is like this:
1st = 1 = 1 missile
3rd = 1 + 1 (complete set of two levels) = 2 missles
5th = 1 + 2 (complete sets of two levels) = 3 missles ... etc.

So, Greater Magic Weapon says that a weapon (or ammunition) gets +1 per four caster levels. I would think it goes like this, although I do ccasionally get it mixed up:

[Assuming wizard caster since that is the earliest this spell can be cast]
5th - 7th = 1 (complete set of four + change) = +1
8th - 11th = 2 (complete sets of four + change) = +2
12th - 15th = 3 (complete sets of 4 + change) = +3
16th - 19th = 4 (complete sets of 4 + change) = +4
20th - up = 5 (complete sets of 4 + change) = +5

I think that should be right. Essentially, as your poll sugegsts ... divide by four and round down.

Edit:
To demonstrate how this works for Shield of Faith as discussed by the previous poster...
1st - 5th level = +2 + 0 (complete sets of six) = +2
6th - 11th level = +2 + 1 (complete set of six and change) = +3
12th - 17th level = +2 + 2 (complete sets of six and change) = +4
18th - up = +2 +3 (complete sets of six and change) = +5

moritheil said:

So you are saying that RAW favors dividing by four (and not rounding up), the way I have previously adjucated it?

Thanks.

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Absolutely.

moritheil said:

So you are saying that RAW favors dividing by four (and not rounding up), the way I have previously adjucated it?

Thanks.

Click to expand...

Right. It's why some spells have an important "minimum of 1" note - Divine Favor, as an example.

"Calling upon the strength and wisdom of a deity, you gain a +1 luck bonus on attack and weapon damage rolls for every three caster levels you have (at least +1, maximum +3)."

If the 'at least +1' note did not appear, the spell - castable at 1st level - would do nothing until 3rd level.

At CL 1: How many 'three caster levels' do you have? None. +0.
At CL 2: How many 'three caster levels' do you have? None. +0.
At CL 3: How many 'three caster levels' do you have? One. +1.
At CL 4: How many 'three caster levels' do you have? One. +1.
At CL 5: How many 'three caster levels' do you have? One. +1.
At CL 6: How many 'three caster levels' do you have? Two. +2.

Fortunately, the 'at least +1' clause means CL1 and CL2 actually see some benefit.

GMW has no such clause, so if, for example, an Ur-Priest casts the spell at caster level 3 (I'd need to check the maths, but I believe it's possible), he will actually obtain a +0 bonus from it.

-Hyp.

Hyp - this is also true of a cleric who for some strange reason deliberately lowers his caster level, right?

Thanks, everyone!

moritheil said:

Hyp - this is also true of a cleric who for some strange reason deliberately lowers his caster level, right?

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No, because a cleric cannot cast GMW at a caster level lower than 5, so the +0 never kicks in.

A 20th level cleric can cast GMW at a CL of anything from 20 all the way down to 5, but he cannot cast it at CL4.

-Hyp.

Ah, I had forgotten that one cannot lower CL below the minimum needed to cast a spell.