Leiron,

Here's possibly a better way to conceptualize it.

We're looking at two different things when with Fracture here. The first is damage per usage. This is relevant for "burst" fights. Does it cause an increase in DPS when used? One of the ways to determine this is to compare to what we would be using instead. Normally, this would be a single ability, but here we use combos. We look at the average damage (potency) of the combo. Is it greater? Yes. So, on a shorter fight, we use it if X is met. X is the number of ticks that it are required in order to be superior. A burst fight is where a TP pool may come into play.

The second thing is a long term fight. All we need to know here is damage (potency) per TP and not on a net basis. Is it more efficient here? Yes. So, on a longer fight, we use it if Y is met. Y is the number of ticks that are required in order for it to become more efficient. This ignores TP regeneration because it is irrelevant. By looking at the most efficient usage of TP, it doesn't matter when if things slow down which they will eventually. Fracture does not run you out of TP significantly that much faster. It costs 2.67 TP a second, 6.67 per GCD if you spread the cost over the duration you want it to run.

Typically, in these circumstances, when we think in terms of efficiency, we are considering things that stretch out what we do over time longer. That is typically the case, but it is not always the case. When comparing Fracture to non-Fracture, there are essentially three phases if you want to conceptualize it.

1.) Fracture rotation and non-Fracture rotation both have "TP pools" undrained.
2.) Fracture rotation having a drained "TP pool" and non-Fracture having an undrained "TP pool."
3.) Both rotations having a drained "TP pool."

In phase one, Fracture rotation builds up a damage advantage over non-Fracture rotation. For phase two, the non-Fracture rotation has the advantage. It begins cutting into the damage advantage that the Fracture rotation built up. However, phase three occurs before the non-Fracture rotation has overcome its disadvantage from phase one. In phase three, the Fracture rotation has the advantage.

We know that the non-Fracture rotation will always be superior because it is both more efficient and more damaging. Let's pretend that the Fracture rotation were simply more damaging but less efficient. It would build up an advantage over non-Fracture in phase one. At some point after phase one, the non-Fracture rotation would overtake it permanently.

It's not the complete picture, but for practical purposes, it is most of it. You can create some odd situations like the 1000 TP 3750 potency attack. It immediately starts in its phase three. However, because all of its damage is completely frontloaded, it distorts things. All things being equal, frontloading damage is always better. The damage is so heavily frontloaded that the standard BB combo which I used for comparison, does not overcome the initial burst until the 18th GCD. If both were putting out what they averaged per GCD, the big attack would be at a disadvantage until the BB combo ran out of steam (which it does at 75 GCDs I think). So for GCDs 18, 19, and 20, the BB combo is superior. If the target were to die in these GCDs, the BB combo would outperform the giant attack. Every cycle, it gains ground on the giant attack. However, it is inferior a majority of the time before for it runs out of its "TP pool" and forever after it runs out. Such is the power of frontloading.

This relates to Fracture because, in a sense, it is frontloading your damage and is more efficient.