Magic Item Creation:Speed stacking?

[hector212121]

I'm curious as to how these three things stack.

Forgemaster halves time to create metallic items.
Cooperative Crafting, such as from a Valet, doubles crafting speed
Accelerated crafting for +5 dc doubles crafting speed.

Now, I think this results in a 6000 gp item being crafted in one day, given that it is mostly made of metal; is this correct?

To clarify logic:

Doubling is additive, as in +100%; the progress is doubled twice, while the progress needed is halved. Progress/needed=300%/50% or 600%.

[DM_Blake]

That seems right to me.