@freemangordon, I wrote a little script that stepped through the clockspeeds using the 'kernel-config lock' command, running a 'kernel-config show' and then sleeping 15 minutes and then running it again. It also copied the content of /sys/power/sr_vdd1_voltage before and after the 15 minute sleep. The phone was otherwise idle.

I've attached the results.

Still no variation in the numbers given by kernel-config show, though... any ideas?