Does the Master Alchemist feat time-halving stack with Itself?

[Mordo the Spaz - Forum Troll]

Think this with me...

I big troll Master Alchemist who can make Brewed Reek (40 gp, DC 25) ten times faster. No question there. By self takes 1.8 hours to make nice stinky Brewed Reek.

base DC 25 + extra DC 10 = 35 DC
Craft check also 35. 10 from Take Ten + 5 comp. bonus + 2 circ. bonus + 2 Master Alchemist untyped bonus + 16 Skill
Then (check * DC) / 7 days * 8 hours = 21.9 gp per hour
So 40 gp cost / 21.9 gp per hour = 1.8 hours

Also have Leadership and five followers of single level: all Wizards with Cooperative Crafting and Valet Familiars who also have that feat. So me happy little group have ten helpers.

Each can use Aid Another for untyped +2 bonus. That increases Craft Check to 55. Time per Brewed Reek down to 1.16 hours.

Each can also "double speed".

Cooperative Crafting wrote:

You provide a +2 circumstance bonus on any Craft or Spellcraft checks related to making an item, and your assistance doubles the gp value of items that can be crafted each day.

(I read that final sentence of the Cooperative Crafting text as halving the time required for crafting, since the feat cannot be doubling the length of the workday.)

Here question: How does "double speed" stack?

Does help of ten Cooperative Crafters mean make Brewed Reek in 1.16 hours * (1 / 10) = 7 minutes? With ten helpers it takes one-tenth as long

Does help of ten Cooperative Crafters mean make Brewed Reek in 1.16 hours * (0.5 ^ 10) = 4 seconds? Each of ten helpers halves the time

Either way job can be done in between dungeon rooms. Put magic cauldron on wheelbarrow to keep handy.

[Joesi]

I'd say it definitely doesn't half the time per person, but rather adds one person's worth of crafting speed (hence stacking is additive not multiplicative). Personally I never knew about this rule, and frankly I think it's inappropriate, especially for situations of more than 1 person aiding.

While on this topic, I have my own question. I guess all this boils don to GM rule, but I wonder what people's opinions are of this:

- Can one make a single craft check for crafting multiple items (what if they're all the same item)? The main reason I ask is because of crafter's fortune (which only affects 1 check). Personally it seems fair to allow it since 1 expensive item shouldn't gain any advantage over a bunch of cheaper items; things should be balanced so that it doesn't matter whether the items crafted are expensive or cheap; penalizing small crafted items seems lame.
- (bonus question that seems kinda common-sense answer)Can more than one craft check be done per day? it doesn't mention the possibility of having smaller increments than for one day, but doesn't disallow it either. Personally, it makes a lot of sense, since otherwise crafting certain cheap items would be really terrible.

[Diego Rossi]

Mordo the Spaz - Forum Troll wrote:

Each can also "double speed".

Cooperative Crafting wrote:

You provide a +2 circumstance bonus on any Craft or Spellcraft checks related to making an item, and your assistance doubles the gp value of items that can be crafted each day.

(I read that final sentence of the Cooperative Crafting text as halving the time required for crafting, since the feat cannot be doubling the length of the workday.)

And that is where your problem is born.

The only thing that affect the speed at which the primary character work is the +2 to the skill check, what the feat do is to add the work of a second character. So you don't halve the production time, you add the production capability of another character, doubling the output.

Notice that there is a specific rule about how multiplying work when stacking effects:

PRD[ wrote:

Multiplying: When you are asked to apply more than one multiplier to a roll, the multipliers are not multiplied by one another. Instead, you combine them into a single multiplier, with each extra multiple adding 1 less than its value to the first multiple. For example, if you are asked to apply a ×2 multiplier twice, the result would be ×3, not ×4.

While the rule speak of "multipliers to a roll" it should be applied in almost any situation in which multipliers appear.

Stacking the master alchemist feat is another problem. As I see it your helpers don't benefit from it (the feat speak of you).
So you don't get master alchemist, production x10
master alchemist with 1 helper, production x20
2 helpers, x30 and so on,

but

Master alchemist, production x 10
with 1 helper, x11
with 2 helpers x12 and so on.

Your master can see it differently, so ask him.

[Piccolo]

Probably not. Remember, you can only take a given feat once, unless it specifically states otherwise.

[Kazaan]

Based on how factors multiply in pathfinder, it'd work as follows: 1 cooperative helper doubles the sp value per day (effectively halving the time it takes) so 2 helpers would triple it rather than quadruple it. So 10 helpers would do it in 1/11 the time, not 1/1024 the time. Master Alchemist lets you use base gold cost of the item rather than 10x base gold cost in determining how much you can craft in 1 day while helpers increase the gold value you can apply to that cost in the work day so they work on completely separate parts of the equation.

Normally, without the sp benefit from Master Alchemist (but keeping the check bonus for parity):

Base Price: 400 sp
(35 Check * 35 DC) / 7 = 175 sp worth of progress per day
175 sp/day / 400 sp/item = 0.438 items per day

Then, you add in +20 bonus from 10 helpers (still not using the double speed bonus)

(55 Check * 35 DC) / 7 = 275 sp/day
275 sp/day / 400 sp/item = 0.688 items per day

Now, we calculate it with the Master Alchemist multiplier and the Helper circ. bonus, but not the helper multiplier:

Base Price: 40 sp (because of Master Alchemist)
55 Check * 35 DC = 275 sp/day
275 sp/day / 40 sp/item = 6.88 items per day

Now, finally, we account for the Helper multiplier which adds value per day crafted:

55 Check * 35 DC = 275 sp/day
10 helpers = 3025 sp/day (275 * 11)
3025 sp/day / 40 sp/item = 75.6 items per day

So, the base price adjustment from Master Alchemist with the double crafting speed from each helper brings you from 0.688 items per day to 75.6 items per day.

Now, at about 529 Brewed Reeks per week, you pay 133 sp in raw materials for each one so 70357 sp (7036 gp) and, selling them for 200 sp each, you earn about a 50% profit, netting you 3545 gp for the week. Presuming you can find buyers for mass-produced Brewed Reek. This also doesn't take into account labor costs as those 10 wizards would probably be expecting 1 sp per day of work so that's 70 sp for the week. Then you have the capital cost of the Cauldron, etc. etc.

[Mordo the Spaz - Forum Troll]

Think Diego wins prize.