Is "Zero Latency" the same as "Clean Switch" w/ Videohub?

I am running two sync-rolled Millumin systems outputting from BMD Decklink cards. I want to know if I use the BMD Videohub as a failover switch, when I switch the 4 main outputs to the backup outputs on a macro button, will the projectors loose sync and need to require the signal which will make them flash or dip to black. Yes, I would always have the 3 units locked together with a genlock source.
So essentially looking for a answer to my subject line: Is "Zero Latency" the same as "Clean Switch" w/ Videohub?
Thanks,
Rob