With a 30 kilometer radius turnpoint cylinder, if you add the half
percent error band to the cylinder (150 meters) you gain twenty seconds by
turning earlier assuming that you are flying at 33.55 mph, or 15 meters/second.
With an error band of 0.05% you save two seconds.

With a 400 meter radius turnpoint cylinder, if you add the half percent error
band to the cylinder (2 meters) you gain 2/15th of a second by turning earlier
assuming that you are flying at 33.55 mph, or 15 meters/second. With an error
band of 0.05% you save 2/150th of a second.

I just published an article which showed an error of up to 257 meters. How do
these error band designations affect that level of error?