You need to be careful with comparing reach measurements across different sizes that also have different stack heights. Once you add the extra spacers to the smaller sized frame to get a given effective stack height, you are also reducing the effective reach.

For this reason, when you are looking at which frame size to get for a certain needed final stack height (including spacers) the difference in reach between sizes is usually a bit greater than the reach measurements listed for the different frame sizes would lead you to believe at first.

They may have used the tall headset spacer stack with the straight stem in order to leave the steertube long if this was a test bike. I did the same on my bike until I knew exactly where I wanted to run the bars.