Too fast vs too slow

If you look at the lines on the bottom of this graph:
http://soaringcafe.wpengine.netdna-c...io-Polars1.jpg

You will see the glide ratio plotted versus the speed. For every speed this diagram gives you the glide ratio for that speed.

If you then look at the optimal glide point, that is the point where graphs reach their lowest point (the Y-axis is on the right for these graphs), you see that on both sides of this peak the line
has roughly the same slope. This leads me to conclude that it does not really matter, for this particular aircraft at least.