The voltage is not fixed for each frequency, so it is modified while working, and the only thing that is fixed is the nominal value.
I have looked very little about this board, but that is what I have seen so far.
I made a compilation reducing the nominal value, but do not think it changes much.
I've also tweaked some latencies and have limited the overclocking to 1Ghz (better relation).
I've done some testing and I can see that using ondemand, the lower rate (300Mhz) is much more used, so consumption should be reduced.
HTC Desire (unbranded, Runnymede AIO)
Asus Transformer (Revolver 4)