If the position does meet the higher standards you can always formally review a desk audit and the result could be that it says you're doing GS13 work, so they then have to either promote you or reassign some tasks to take your position back to a 12 level. You could also theoretically have an audit say your work does not support your current grade but that sounds unlikely in this situation.
Hmm. I've never heard of this. How is a desk audit conducted? Is it just through HR, or is the manager also involved? I saw one duty in the description that I don't perform, but that's only because someone else does it (One of the people I believe will be promoted) and it's a really simple task--something an intern could do. I've certainly done work that's above and beyond my own job description, but if proving that involves asking the manager, I'm certain he'll lie.
And that would really piss me off because our PMAPS in this group are regarded as "just a formality" and something never actually reviewed or discussed. At review time, I go in and "have a conversation" about my work and at the end of it, the manager pushes a piece of paper at me and says my signature just confirms that we've had the conversation. The bullet points are basically the same as my job description--extremely vague--and I'm told "we all do work beyond the job description." But nothing in the paper is reviewed or discuseed and I don't even have a copy of it.
So should I be disputing that practice? I have at least two other coworkers who have expressed their anger that they're not getting the review they deserve based on the extra work that they do, and they're signing a piece of paper that they don't even get to review and discuss first.
I've heard rumors that supervisors in our group are getting reward and promotion based on this "extra work" that underlings are doing while the underlings remain at the same level for years and years. If I could prove that, where would I take it? In fact, there's a lot of managerial abuse at this agency. I often think of it as "Lord of the Flies" because there is so much abuse but our low profile means it flies under the radar. Plenty of people have filed grievance and lost against our big parent agency, and it pretty much discourages anyone from taking action against some really egregious wrongs.