Hey, sorry for late reply. Unfortunately I don't know much about about the sampling_rate etc, but from what I understand it is the frequency that the cpu load is checked to adjust the clock speed as appropriate (ondemand_governor), so if the clock speed jumps up it should be because something is loading the cpu. As the Pulse has old hardware I guess it makes sense that basic tasks would load the cpu?
Not sure what cpu monitoring app you're using but I personally use the latest setCPU for monitoring/checking that kind of stuff. Also as you had the app open that would prob explain why the cpu clock kept jumping up as it was loading the cpu doing it's monitoring. I guess increasing the sampling_rate might reduce how often the clock speed jumps up, but that may also mean a reduction in performance?
With regard to my set up, I've never used DT. I use a couple of firerat's scripts (not sure if they will do every thing you would want though?) for apps2sd. And I have a swap partition that is controlled by a script in init.d. Haven't played with the pulse for ages but I basically have a modded rom of what Tom released. Think I deleted some of the default apps so maybe that had an effect? If you can connect your phone via adb maybe do a ls of your /system/app/ directory & paste it up so I can see what I've deleted?
I guess there's also the possibility you have a dodgy battery :D The above is also all speculation by the way, I don't have any specific knowledge on the matter at all lol!
Sorry, I don't even have access to the pc that has all the source files etc anymore. I'm pretty sure someone posted one somewhere though, as I remember helping him calculate the numbers?