Wired Flow Meter Location Before or After BFP

Can anyone confirm that a wired flow meter should be installed after the backflow preventer? I’m 99% sure this is the case, just needed confirmation. I’m using a Toro TFS-100 flow meter, I assume this will be wired to the S1 on my Rachio 3 and the 24 VAC + terminal. Or should it be in the - (negative) VAC terminal? Thanks

It is my understanding it can be before the BFP if the meter is approved for drinking water since the water “contaminated” by the meter could trace back to the main supply. The Everydrop is not approved for this, but practically doesn’t seem to have any materials that it couldn’t be, just didn’t do the paperwork.