Yeah I was just curious how much it costs you when it is idling vs how much when its 100% chugging along.
Yes, that does make a bit of a difference. I don't know exactly how much of a difference, but... yeah. Oh, I should also point out that I don't usually run all of my PCs all the time (as is typical for a mining operation), for exactly this reason. A single PC has lower power requirements, but correspondingly lower returns. You can't really do much with just one PC. Generally you want several PCs each with multiple GPUs, or else some kind of specialised hardware. Not to mention some means of powering the whole operation that costs less than the bitcoins you're mining (this is where the whole plan falls apart, at least in Australia).
With electricity prices being what they are, the very idea of running all these machines 24/7 at 100% load makes me cringe. A more specialised setup (eg FPGA) would be cheaper, but still nowhere near cheap enough. 
