Our very own Reglitch recently posted this on his blogthing: http://bestmonk.eu/?p=100 (Edit: Nevermind, Reglitch later on deleted all his MoP blog posts in favor of Warlords stuff. This is talking about Soothing Mist and pushing ticks under integer numbers of seconds.)
Now my post.
First, recall this post from main thread (or if you didn't read it, skim it now or even click it and read the surrounding posts if you want):
To be perfectly precise, despite what I said in my post above, this is going from 42.80%, roughly 9158 rating, to 50.01% Haste, 12154 rating. (You can see in below discussion that I originally thought it was 12145 rating, which i got from Ask Mr. Robot as being 50.01% Haste, and why that was wrong.)
So as we see here if you're using SooM correctly (spamming it) then you get an extra tick if you channel for 2 sec or for 4 sec but not for 1 sec or 3 sec (any more time than that is probably somewhat irrelevant). We could call this a Soothing Mist Haste pseudo-breakpoint for 2- and 4-second channels.
But this argument was what happens at just above 50% Haste, which is at 12154 Haste rating (before you enter serpent stance and get spell haste buff, anyway). The testing Reglitch did in the linked post was done at the 12138 Haste breakpoint, 49.98% Haste again according to AMR. It's pretty clear to me that the extra 16 Haste Rating needed to push to extra SooM ticks is worth it. The "perfect play" model Reglitch used in the Haste post uses a lot of SooM for chi generation, so Effective Uplifts for 9158 compared to 12145 (Edit: 12154) should merit discussion, not 12138.
Assuming I've made no mistakes.
FOLLOW-UP: Complete list of Soothing Mist Haste Pseudo-Breakpoints: For Reference
Summary of follow-up: The 12154 breakpoint occurs at 14178 without raid haste, and is still worth jumping up to without raid haste, if you were actually hitting the 14162 ReM breakpoint. There are likely no other important SooM haste pseudo-breakpoints.