Back when I first joined, around a month or two in, I did something similar with Etoru. I wanted his progression to be kind of slow, yet have his potential be something great. So I just flavored Ki Suppression as hidden potential.
I would doubt a player would end up spending weeks without getting so much as a grade for something that was put up for grading. Mostly because it would take all of the staff team being too busy for some reason, for it to take that long.
Furthermore, the rules are there to keep a cohesiveness in the story that would otherwise be broken. If people could lower their power without a tech for it, then we'd have other problems. Sorry you don't get to have a special snowflake situation, but you have to adhere to the rules as they are.
You do need suppression to lower your PL from what it is. This is to prevent people from trying to metagame a fight without paying any kind of cost, so it's one of those instances where gameplay considerations have taken the upper hand.
However, you received a grade for a thread that put you at well above just 400 PL roughly 4 days before the incident in question. So your PL had grown due to training, and your power increased. You started a new thread, and claimed your power level was lower. This is considered lowering, by our definition, and thusly is not permitted.
Special Snowflake? Wanting to be able to roleplay my power increases like almost any other successful story is being a special snowflake?
What sort of special snowscape am I roleplaying in here....
However, about the thought process you have as a writer, major improvement doesn't happen "off-screen," it happens during the thread you attained your gains in. I'm not aware if you've ever done so, but when working out, you're stressing your body so that, when you sleep and rest after, your body can begin it's healing process, strengthening the parts of your body you worked out. So that is quite literally how physical growth takes place.
Supernatural as it may be by our standards, it still has it's basis in real world ideas, thoughts, and mythologies. Gravity training, for instance, is quite literally working out. Ki in the dragon ball universe isn't magic, theres a separate energy source of magic that functions differently. But I can understand the misunderstanding.
And in that case, it sounds like you have the basis for a character aspect such as a mental block preventing her from using her full strength until she is forced to do so. And as you've stated before, you've now got techniques to make it actionable in RP.
That being said, this thread has been resolved I believe, unless you have further questions?