Decreasing Crafting Time

[xiN.]

If I have 8 hours a day to craft, can I increase the DC of the spellcraft check to DC+5 and craft 2x 4h for 2000gp worth of crafting. And can I increase it by another +5 and do 4000gp per day?

As far as I can see the only limit is 8 hours max per day, and you can double your crafting speed for every +5 you add to the DC.

Am I right?

[Karui Kage]

You can only double the crafting speed once. So if you are crafting a 4,000 GP market price item normally, it would take 32 hours, 2,000 GP, plus any required spells and such. If you increase the DC by 5, the time required would drop to 16 hours. That's as low as you can get it though.

[Carpjay]

Brew Potion and Scribe Scroll feats have special exceptions in the feat descriptions about items with base value less than 250 gp taking only 2 hours to create, but then jump right up to 1000gp value and a full day. Other types of crafting seem to stick to the general rule and the specific craft item feats.