Just wanted to chime in, with some very simple bash scripts. I'm using these, since I'm running SABnzbd behind a reverse proxy, but I'm sure they work fine using local addresses as well.
pauseSAB.sh (before mover starts)
#!/bin/bash
# SABnzbd API key
API_KEY="insert-api-key-here"
# SABnzbd URL
URL="https://sabnzbd.domain.com/api"
# Pause command to SABnzbd
curl -s "$URL?apikey=$API_KEY&mode=pause" > /dev/null
resumeSAB.sh (after mover ends)
#!/bin/bash
# SABnzbd API key
API_KEY="insert-api-key-here"
# SABnzbd URL
URL="https://sabnzbd.domain.com/api"
# Pause command to SABnzbd
curl -s "$URL?apikey=$API_KEY&mode=resume" > /dev/null
The scripts work fine and pauses SABnzbd instantly. I haven't tested them extensively with the Mover running yet, though. But they do as advertised - pauses and resumes SABnzbd's downloads :)