Sorry this is partially incorrect for today's modern drives and media.
A burn speed higher than the rated speed can also get good or better result, especially if the drive's firmware is optimized and the media quality is very good. We have seen numerous tests done by members particularly in the DVD burner section and Blank Media forum.
However, burning at many times higher than rated speed, for example 8x rated DVD-R burn at 20x or 24x, the outcome might be worst than burning at rated speed, although it is possible that the result is still within standard of a good burn.
As for this Pioneer BDR-203, you can't burn BD-R/RE lower than 2x, in other words, you can't burn at 1x as you suggested above.