I am a 92A20 (SUPPLY), however, I have been working as a 92Y30(Org Supply) for over one year. Also, I have been to a 40 Hour Block of Instructions for the 92Y position. How do I go about including another MOS on to my ERB?
Did you go to the actual AIT for it? Do you have a 1610 staiting that you've successfully completed and earned the MOS of 92Y? If that is not the case then you're not officially awarded the MOS. The 40 hour class you've attended may just be something that will appear under your military education section of your ERB as a course you've attended.
Unfortunately unless you have actually attended the AIT it does not count as a secondary MOS. If you're an NCO you can have it put as your job title for your NCOER otherwise don't worry about it, if you stay in the army long enough you will have enough additional duties and if you want to switch your MOS get with your Career Counselor.