Salary adjustments can be adjusted at your grade, but your grade progression cannot be accelerated. Meaning if your skills + competency is assessed to be I, but they offered G due to the wonderfully good deal expected salary, and you accepted it, there's no avenue to ask HR to retroactively readjust your grade, you will have to suck thumb suffer this grade latency in Govtech (or any public agency for that matter) for as long as you stay there.