pgdg96 repo with centos 7.x - server starts only on loopback

hi fellas

I'm using PostgreSQL 9.6 7 - x86_64 repo with centos 7.3.
Configuration pretty standard, including this among the lines:
...
listen_addresses = 'localhost, 192.168.2.200, 10.5.6.100'
...
and yet, after system reboot I get process listening only on:

tcp 0 0 127.0.0.1:15432 0.0.0.0:*
LISTEN 5373/postmaster
tcp6 0 0 ::1:15432 :::* LISTEN
5373/postmaster

all I have to do is to:
$ systemctl restart postgresql-9.6
to get expected results.

Is this not bizarre?
I peep into systemd's Unit and there:
...
[Unit]
Description=PostgreSQL 9.6 database server
After=syslog.target
After=network.target

seems ok, right?
What can be wrong?
many thank
L.