Yes, you would create items at a truly insane speed, but you're also a 15th-level character by the time you can pull this off.
Basic overview of the "standard" Craft workflow:
- Calculate the item's cost in sp. That's your target value.
- Multiply your Craft check by the item's DC (assuming success). That's your weekly progress. Keep a running total of that value.
- When you reach or exceed your target value, you're done. If a single check doubles/triples/etc the target value, you finish in that fraction of the time.
Looking at the Skill Unlocks portion of Pathfinder Unchained, you'd get the following benefits:
At 5 ranks, the progress you make in Step 2 is doubled. It's still your weekly progress, though.
At 15 ranks, the progress you make in step 2 is daily, not weekly. Don't multiply your check result, just reduce your time scale.
When you take the Master Alchemist feat, your target number in Step 1 is just the gp cost and is not multiplied by 10. Don't multiply your check result, just adjust your target. You're still taking an entire week to craft an alchemical item, however. The general assumption is a 5-day workweek with 2 days off, much like modern life. As such, you can divide your progress by 5 to determine your daily progress instead. Since your target is much lower, this can eliminate extra crafting time.
Keep in mind that, as an Alchemist, after 3rd level, the time to craft alchemical items (but not poisons) is halved. As we're about to see, that makes all the difference.
To take an example, suppose you're crafting alchemical glue (20 gp, DC 20).
At 5 ranks (total +17 on the check [5 ranks, +5 from Alchemist, +3 for class skill, +3 Int bonus, +1 portable lab], taking 10), the process would be as follows:
- Target number is 200 (20 gp x 10)
- Progress per half-week would be 27 x 20, or 540, doubled to 1080. Progress per half-day would be 1/5 that, or 216.
- It would take you a single day to craft a flask of alchemical glue. It only takes 4 hours if you're an Alchemist, so you could make 2 per day.
At 5 ranks and the Master Alchemist feat, the process would be as follows:
- Target number is 20 (20 gp, no conversion).
- Progress per week would be 27 x 20, or 540, doubled to 1080. Progress per day would be 1/5 that, or 216.
- Since your result is 10x the target, you finish in 1/10th the time, or 48 minutes (8 hours is 480 minutes). An Alchemist would need only 24 minutes. You could make 10 or 20 per day, respectively.
At 15 ranks and the Master Alchemist feat, the process would be as follows:
- Your target number is 20.
- Progress per day would be (15 ranks, +15 from Alchemist, +7 Int bonus, +1 portable lab, taking 10) 1920.
- Since your result is 96x the target, you finish in 5 minutes (480 minutes / 96). An Alchemist finishes in 2.5 minutes. You could make 96 or 192 per day.