Quality is also affected by your rotation of the piece on the fabric when you cut it out. If you don't "align it to the grain line" (rotate it so the arrows point left/right) the quality of that piece will be capped.
It would be nice if they'd clarify that more (in they don't already) in the tutorial. It makes sense now you say it, but not something I'd expect or assume and my focus has very much been on saving fabric
