Someone actually asks him in that thread if they are needed and he says only 1 person out of 30 or so has needed them.
Reground cams are typically made by building up the lobe peak by welding and then regrinding it to the desired profile. During regrinding the whole lobe will be ground, including the side of the lobe where the valve is closed. That side of the lobe did not have any extra material added, so in order to set the valves you will need to adjust the eccentric farther than you would typically have to. Sometimes the stock valve eccentric might not have enough adjustment to set the valves properly so you have to install an eccentric that is oversized in order to compensate.