Even while playing Music or running a movie, the CPU is not ON all the time. A lot of that is done via the DSP anyways, so your CPU would remain idle a significant amount of time (as an example, play an mp3 and run Conky and you would see that the CPU is usually at 500MHz if you are running ideal). So while the test is valid, the premise isn't. Also, to sample current properly, unfortunately once every second isn't enough. You are talking more like 30 times a second, given how many times the CPU is waking up every second.

Having said that, there is definitely a compromise frequency, which would vary from device to device. So for ideal, it could be 600Mhz but for LV, it could be lower.