How do I approach my NCOER after getting promoted just before my thru date, my supervisor moved into a new position, and I barely know my PL?

Your rater only needs 90 days to rate you. You should always provide all your accomplishments to your rater throughout the year. One very easy way to do this is to open your own NCOER support form and plug those in throughout the year.

You don't need to have your through date to August you are due for a change of rater. Alternately, you could have an extended NCOER.

That's about all the easy answers I'll give you because as an S1 the people in your unit will be coming to you to answer these types of questions. You will be considered the subject matter expert in your unit for NCOERs, Platoon Sergeants and First Sergeants will be coming to you with these same questions. Evaluations are one of the core competencies for HR and this will be your bread and butter once you're the NCOIC of a shop. You will need to check out the regulation and the DA Pam. I also recommend some of the FAQs on the HRC website and getting onto S1Net. I highly recommend getting into your local AGCRA for the outstanding mentorship that's available in most chapters.

That’s where a change of rater NCOER comes into play. Your direct supervisor SHOULD have done one before he/she moved positions.

Speak to your S1 NCOIC to ensure you are properly rated. If your rater moved internally he can rate you for the period up to the month he transferred. If 90 days remain between that rating and your promotion you will receive another for that period. Your situation is very normal and nothing to be concerned about. Whether your leadership is new or not has no bearing, you are rated on performance, perform and your new NCOIC will rate you appropriately.