I’m fairly certain that you can get time as OICNW without having to hold STCW OICNW at all. Example, working as mate or master on a coastal tug less than 200 GRT (exempt from STCW) with just a domestic license. Therefore, your time working under II/3 should be fine, as well as the time from before OICNW existed.
(If your time was as master you might need to prove you actually stood a navigational watch in order to use it towards time as OICNW.)