Maximum Pay Rate vs. Highest Pay Rate vs. Two Step Rule (for promotion)

Some quick facts:

• Resigned from fed gov in Dec 2019 (wanted to "retire early")
• GS-13, Step 1 (~$90K) upon resignation
• Got bored so I applied/was hired for a position with a different fed agency (GS-9T11) in Apr 2021
• Onboarded as a GS-9, Step 10 (~70K)

My one year mark is coming up soon. When I was hired, I was under the impression that MPR/HPR would continue when my promotion kicks in (GS-11, Step 10, ~$84K). I sent an e-mail to HR asking if there's anything I need to do on my part regarding the promotion and they said "no". I then wanted to confirm that my promotion would be Step 10 (GS-11, Step 10 pay would still be lower than $90K).

Well, they came back stating that I would fall under OPM's "Two Step Rule" and would only get GS-11, Step 5 upon promotion (which is $11K less than what I was expecting). So, I went and looked at OPM's website, along with 5 CFR 531.221 through 531.223, and it looks like the maximum pay rule CAN be used for promotions...but it is up to "agency discretion".

First off, I'm wondering whose "discretion", in the agency, is needed exactly to approve a promotion above the Two Step Rule (to a Step 10 via MPR rules)? HR? A branch/division chief's recommendation? The agency Secretary? Agency discretion is a pretty vague term IMHO. My gut tells me to send an e-mail to my immediate supervisor with my concerns and have them run it up the chain but wanted to get input from the boards beforehand.

I know, at the end of the day, an $11K difference is not going to cause me to go hungry...but if I'm entitled, I might as well fight for it.

Any advice/info would be greatly appreciated. Thanks!