I'm glad to see that others of you have had a similar experience with the chart.
That means I MIGHT not be going nuts yet.
I may be wrong about it being an "intentional error", but the hunting chart sure does result stiff.

Regarding speed, you just choose a lighter arrow WITHIN the correct spine range for your setup.
If you go outside that range to go lighter, of course your flight and groups will suffer.

My objection was only that the chart seemed to be misleading and gives you the wrong spine to start with.