8.25 gear install, grinding required to pinion?

I read a note about the Superior 4.56 gears, saying that grinding may/will be required on the pinion, at the yoke end.

Any idea what this is about? I know some setups need a little grinding to get the cross shaft in place (unless you use the notched shaft), but is this what that means?

Just a little leery about stuff requiring grinding to a critical part like gears.

grind the cross shaft (actually the ring gear teeth in front of it)...yes.

the pinion....no