mechanic question: dead ball vs. down indication

[JugglingReferee]

CANADIAN MECHANIC:

Our play clock works differently than the US PC and as a result, we do not have a need to raise our arm when we rule the play dead and mark forward progress. However, we do square up on the sideline (with the odd exception), and use our whistle. If necessary, stop the clock.

At this point, there are many styles you will see out there, but the general process is to wait for the official signal from the Referee to each sideline before giving the next-down signal to your partners/crew. This could be because we place the onus on the R to prevent each multiple sources of incorrect signals.