Couple things to keep in mind...
Your phone has 3 settings; Idle, min, and max.
In terms of frequencies, above 480, they system increases voltage. 120, despite being in the menu doesn't work and even if it did, it would be useless anyhow.
The original testing and thinking (most people never read the follow ups to the testing) was get the work done as fast as possible. That works find on something like compressing a file, in which case do it as fast as you can and get back to idle. The problem was the initial testing and theory was based on work and idle. Remember how the phone has 3 settings? It never accounted for things like navigation, which is low, but long term processing.
Say you have your min at 360 and max at 804.
When your phone is off, it sits idle. You turn it on and open Gallery, it ramps to 804 to finish the job as fast as possible then goes back to idle. Now, lets play an mp3, it might need only 240, so it uses what it needs and it sits there. When you are finished it goes back to idle. No problem so far, right? Now lets take those same settings and stream music, now it may need say 300mhz. Again, no problems, everything is running optimally.
Now, let's do one last thing. Say you want to listen to music and use navigation, this uses a total of
let's say 365mhz. Because you crossed the 360 mark of your minimum by even a mere 5mhz, your phone automatically goes into max power mode of 804. Now you have not only the GPS running, using battery and giving out heat but you are also running the cpu at 804mhz the whole time. After about 20 minutes your phone will be physically warm and lost a lot of battery. I situations where you exceed the minimum for an extended time, 600 is much better than 800.
The goal is to set the minimum just above what you use the phone for the most so that it only ever crosses the threshold when necessary.
For mp3, 240 is probably fine.
For streaming, 360 is good.
For navigation, 360 might be enough, it might not.
480 is a pretty simple setting because it works the best all around, but it's not the very best for everyone, just a good/safe starting point because you are less likely to cross it, and it's the last step before the voltage increase. The difference in power use between the lower settings is minimal compared to the step from 480 to the next setting.