Hi Ian. I will try to explain.
If two pieces of veneer are placed next to each other on adjacent pieces of the design, then they would have have to overlap each other in order to get a cut with two edges that would fit perfectly together. However, overlapping the veneers would create a bulge in the packet which would prevent the packet from maintaining a perfect 90 degree angle to the saw blade. The blade would then be deflected causing an inaccurate cut.
I’ll add this to the blog in case others have the same question.
Mike, an American living in Norway