What drive are you scanning with?
I’ll let someone else go into the technical details, but often scanning speed can/will affect disc quality test results - for example, I scan on an older LiteOn LH-20A1H, and I find the best scanning speed for me is 4x, as anything higher can produce phantom PIF spikes and other strange results. However, the forum standard these days is 8x scanning speed for (newer) LiteOns, I believe.
I’ve also seen many scans done on older NEC drives at 5x.
But no, generally each drive has a specific scan speed that we use on the forum, it doesn’t automatically mean you need to burn at the same speed you scan your discs at. Burn at 18x/20x/22x/24x if you like (or your media/drive will allow it!)
Oh, and don’t forget the importance of the Transfer Rate Test! (Had to get that in :)).
Cue Drage et al with a more technical explanation