Something similar happened to me. Even though I was promoted, job title changed and my salary did increase (also due to a restructure), my duties still fell under the SOC code that we submitted the application under, so we were told we didn't have to notify them of the change.
We were just told when i go for my extension, just to add a little note saying that though your job title changed due to a reorganisation, but your duties were still within the SOC CODE of the original application. Our company lawyer said the note is not necessary, but can be helpful incase you get that one person that wants to ask loads of questions (more of a safe measure).
Hope that helps