Except there is one problem:
100 storeTP is the max. Therefore, a 4hit build is not possible with a 464 delay. (even
FFXIcalculator uses that rule, and won't let you add anymore STP past that point etc.)
The reason is because storeTP works and is calculated as a percent.
Typically any percentile increases will cap at 100%
We know that haste% caps at 80% in this game, but this is obviously because haste is a direct reduction of your weapon's delay. Therefore it has increasing returns the more you add. Adding Haste% is not the same as adding percentages of double attack.
In the case of Double attack, unless SE feels like implementing a lower cap, the maximum cap that it could possibly have is 100%, which would give you a double attack on every hit. Also, in % (percent) increase, double attack has diminishing returns. Adding more DA to your previous DA is less of an increase than adding DA to no DA.
Going back to storeTP: When adding storeTP you are adding percentages.
To add storeTP to your base TP per hit, you are adding a percent of your base TP per hit.
Also base TP per hit is determined by your weapon's delay, based on these formulas:
Delay of: 0 - 180 use: 5.0 + [(Delay - 180) * 1.5 / 180]
Delay of: 181 - 450 use: 5.0 + [(Delay - 180) * 6.5 / 270]
Delay of: 451 - 480 use: 11.5 + [(Delay - 450) * 1.5 / 30]
Delay of: 481 - 530 use: 13.0 + [(Delay - 480) * 1.5 / 50]
Delay of: 531 - 999 use: 14.5 + [(Delay - 530) * 3.5 / 470]
Example: a 464 delay weapon has a 12.2 base TP per hit. If you add 10 StoreTP, then you are really adding 10% of your weapon's base TP per hit, to your weapon's base TP per hit.
So, it's 12.2 * .10 +(12.2) = 13.4 TP per hit.
Or looking at it this way: 10% of 12.2 TP is: 1.2 TP
Therefore, 12.2 + 1.2 is: 13.4 TP per hit.
When you add 100 storeTP, you are adding "100% of your base TP per hit" to your base TP per hit.
Therefore, you are adding all of your base TP per hit. In other words you are effectively doubling your base TP per hit, increasing it 100%.
100 percent of something means all of something.
That being said, the lowest possible delay needed for a 4hit build is 470 delay, which requires 100STP (100% max) to do it.
Math for the above claim:
470 delay is: 12.5 base TP per hit
12.5 TP * 100% = 12.5
12.5 + 12.5 = 25 TP
25 * 4 = 100% TP (4hits to get to 100% TP, with 25 TP per hit.)