Well the issue with this split is we execute tasks in that order when running again the role on a fresh machine:

1. Software
   1. Install dovecot
   2. Launch Dovecot service
2. Config

So the service is started before the config.

That could explain the standard trilogy software/config/service.

Not sure for 2 and 4 lines if the split is needed, but nothing prevents it if we want to standardize the units.