I just did some parsing using this rotation versus the rotation I've outlined. All parses were done for 2 minutes nonstop on 3 targets. I used the DPS dummies in Whitebrim (Coerthas) for these parses. Here are the results:
Rotation: Fire III ==> Fire II (spam) ==> Flare ==> Transpose
Note: Initial Flare of rotation was followed by Convert + a second Flare. This was repeated on CD.
Result 1: 398
Result 2: 387
Result 3: 402
Rotation: Fire III ==> Flare ==> Transpose ==> Blizzard II ==> Blizzard II
Note: Initial Flare of rotation was followed by Convert + a second Flare. This was repeated on CD.
Result 1: 448
Result 2: 456
Result 3: 454
...
(me) Were you also doing Blizzard2 for the Fire2 rotation? Because it's not like you just sit there after Transpose.
(him) No Blizzard II at all in the Fire II rotation. I immediately start casting Fire III as soon as possible after the Flare.