why there is difference in cpu usage seen on winbox (below titlebar) and /tools/profile.
On winbox it shows 12% in profile it shows 82% idle.
which should be considered accurate

Is there any OID for snmp monitoring of total cpu usage (zabbix etc)

OID: .1.3.6.1.2.1.25.3.3.1.2.1

This is working for RB1100AH, not tested other HW.

It's correct. 12% is utilisation. Normally it varies and profiler also takes some time.

I forgot to mention I'm using 1036. OID you had mentioned will only graph cpu 1. I need oid for total cpu usage i;e cpu-load.

In this case you have to search or wait about 2 weeks, when my yesterday received CCR will go in production and I have to rewrite my zabbix-template ...