During this process the slaved axis is temporarily decoupled from the master. And this is when different settings between master and slave will cause problems. Even homing speed.
Especially Homing Speed. Learned that one first hand.
I think you're making a big issue out of nothing. In over 5 years, you're the second person I've seen worrying about this prior to actually using it.
But I've never seen one complaint from the hundreds of people using it on a daily basis. Almost all the routers you see being built on CNC Zone use slaved gantries, and a lot of them do very precise work.