We may use it as a base but also have to look into pamac too. Better been save then sorry especially if you have low battery an update on shutdown via pamac should be avoided when enabled.
Its libalpm hooks specifically … with both pacman and pamac being fronts for libalpm … so it appears at first glance it should work for both already. (the --who flag is just a descriptor)
PS - I might also suggest coupling this with kernel-modules-hook, or kernel-modules-hook-reflink in the case of btrfs, for more comprehensive insurance.