Hi. Has anyone tried the Discwasher DVD calibration disc? A local store is selling it for $3 CAD. However, it's not the price I'm worried about, it's whether I'd be wasting my time with it. The Avia disc is so much more expensive, so it would be nice to know if this is competent. I can't post an URL yet, but partsexpress has it if you search for discwasher. Thanks!