Why would he be pulling any legs?
Well, the winky for starters
There's that famous joke page about how overclocking will allow your TV card to pull in HD from around the globe, so, anyway...
There will be reductions with both frequency decreases and voltage decreases. A voltage decrease has a FAR greater effect though. If you want to shrink the voltage, you'll have to do some soldering and also figure out a stable mhz.
Yeah, sadly my mobo allows me to increase my voltage but not decrease it. It's also set to "Auto" overclock by default, so I think that every once in a while when the GPU freezes up for whatever reason and I reboot, the BIOS claims that "Overclocking failed." Anyway, that's not the point, the point is that my mobo allows OVERclocking but AFAIK not underclocking. And now I've stopped trusting ATITool