That way may not necessarily be 'wrong' but I'd undo the editing to the conf. Per the OWRT Wiki:
By default, NTP client is enabled and NTP server is disabled. Enable server mode:
uci set system.ntp.enable_server='1'
uci commit system
/etc/init.d/sysntpd restart
Speaking of NTP you should consider adding the corresponding upstream IPs to the DNS addresses. DNS can cause some problems in certain common scenarios.
uci set system.@timeserver[0].server='0.openwrt.pool.ntp.org 1.openwrt.pool.ntp.org 2.openwrt.pool.ntp.org 3.openwrt.pool.ntp.org 104.167.241.197 73.239.145.47 142.147.88.111 171.66.97.126'
uci set system.@timeserver[0].use_dhcp='0'
uci commit system