Some interesting numbers on 4.0 BLM

[Galvuu]

1. If you replace B3 with Transpose, and put in half a second of no damage, your 4.x beats out 3.x
2. Your math ignores Thundercloud procs, which would have a larger boost to a longer rotation (less clipping).
3. Your 2.x rotation has 6x F1

You need to sacrifice a F4 to use a TC proc on 4.0. You simply don't have enough AF time to use TC on 4.0.
Alternatively, you TC and replace a F4 for a Fire. This is not the case for 3.X, where you can TC without sacrificing a F4 cast. TC procs make 3.X better. I'm doing 4.0 a favor, if anything.

Transposing is normally a dps loss. You have on average one second and a half of 0 pps (which is already a disaster).
Even if you used some third party thing (like ACT) to keep track of the mana ticks (which I don't want to at all, and shouldn't even be considered), the problem doesn't end there because your F3 to get back into AF3 is also now a 3 second cast (more lost pps).
To make it worse, since you're going into AF3 from UI, you're now even more vulnerable to the mana tick situation, because you might get this odd mana value where you're left with less than 2.4k at the end of the AF cycle (since you came off UI and not UI III).
Your transpose suggestion will just make 4.0 worse, but you're free to show me I'm wrong with pps napkin math or parses.
There's a reason the highest rated BLMs are using mostly the 3.X rotation and not 4.0 one.

Has for the 2.X comment, I forgot B4 in there, which is actually a good catch. Let me update that.
That, the difference is 4% if you B4 on 2.X, or if you a pure 2.X rotation (no B4), about 3%.
Okay, not 2%. I get 3~4% depending on how I use 2.X. The problem holds as before.

EDIT: so I went ahead and calc'd this for you. If you get a super quick mana tick (<0.5s), your pps comes at around 143 (you gain one pps). However, if the tick takes one second or more, you're losing pps (140.8 for one second, and average is 1.5seconds...).
Further, over two rotations, you better pray you get a fast mana tick off transpose, or you're always losing pps on average. It's completely silly that a server tick can mess a rotation up so badly.
At any rate, 3.X beats either of these options in any circumstance other than Foul not being ready for your UI cycle.