I think a lot has changed with the item pricing forum that warrants an update to the rules of the thread. I don't think I have ever seen someone actively try to abuse the rules of the thread, but I do think they have occasionally inadvertently led to confusion.
They were clearly originally meant to keep people from price checking easily shop searched items and prevent spam, but I think they have gone the opposite direction, and now there are 1-2 topics per day, and topics that sometimes do legitimately merit some discussion get shut down.
Worst case scenario if the forum does get inundated with requests for price checks on red ball, the rules could always be tightened back up.
For reference here are the current rules:
SPOILER (click to toggle)
Before Posting
All item pricing questions go in this board, whether it be a battle item, wearable, etc.
Make sure that at the time of posting, your item(s) are not buyable in User Shops, or listed with an asking price in Trades.
Check to make sure that your item hasn't already been recently posted about and priced. This is especially true for potions/elixirs, Mage Amulets, tomes, custom wearables and, retired items.
The rules for the Item Price forum are as follows:
Include in your post the full name and rarity of your item(s). If you are not sure on the item's rarity, you can find that my hovering your mouse over the item.
You may have multiple price check topics so long as they are not for the same item. When your price check has been answered, please change its topic title to something like "Done Please Lock" and/or ping the MiniMod of this board to have it locked.
Be patient for a reply, and please don't go sMailing/commenting frequent price check repliers to price your item (especially if you have already made a topic about it) unless they have specifically given you permission to do so.
Stay on topic! The item pricing board is only for item price checking.
If you're curious about the purpose of an item, if you should use the item, etc., your topic is better suited for the Help & Questions board. If you are looking to sell or buy items, use the Advertising board or the Wanted board located within the Advertising board.
Similarly, if you cannot answer a price check query please do not reply saying things like "I don`t know, good luck finding a price". Not only is this not helpful, it is spamming and will be warned as such.
No bumping topics, either by yourself or by having another user bump it for you. Bumping is considered a form of spam and will be treated as such.
The Basic Site/Forum Rules, Community Guidelines and Terms and Conditions apply to this board. If you have not read these, do so! It just might save you from doing something against the rules and getting warnings, or worse.
I think this rule has become problematic since raising the max price to 100mil. With some rarer or newer items, just because someone put a brand new r89, doesn't mean it is worth 100mil. But that is sometimes used as a reason to shut down the board. Even back when the max price was 50mil, you would occasionally see riptide price checks that would be shut down when there was one priced at 50mil, but they would regularily sell at 20-30mil. I don't think anyone ever actively abused locking their riptide threads to get a higher price, but I definately had people quote locked riptide threads to me when I was buying/trading for them.
Some staple items like tomes or mage amulets would also not be an unreasonable thing to price check. The price of mage amulets regularilly drops 50-150K below what they would actually sell for due to autopricing. Tomes usually being the opposite where the lowest market price availible is usually higher than most people are willing to pay in bulk. Someone asking what they should price those items at would be reasonable even though there are likely several priced on the shop search.
I would change this to actively say that you are not allowed to change the topic name. Having the topic name remain in the title makes it much easier to find if someone has discussed the item recently. I would also argue that topics in the pricing forum should generally not be locked unless it is for some item that has a well established market like Red Ball or something.
To facillitate easier browsing of the forums I would suggest these rules: Only 1 item or group of related items, which should be included in the Topic name (Ie recolors of some CW could form a single topic, but a collection of unrelated CWs should be split between topics) No changing the topic name No locking until necro rules kick in.
I think one thread that sort of embodies why these rules would be helpful would be here: Burgundy-Handled Magic Broom
It was a relatively new item that was rare on shop search, that people made crazy claims of value on. Supposedly people had been paying these crazy prices, but I really didn't make sense by even the most aggressive metrics of value. It was locked with the conclusion being that this item had the potential to be very expensive for a decent length of time. 2 months later, and the item is 5mil down from the "100mil" valuation that was kinda implied by multiple well meaning people. It would have been an interesting item to follow up on, now that the price dropped. And since the topic name had been changed, it was somewhat difficult to find to link here.
[Center] [tp=thesovereign] :dmg🔥 [tot=thesovereign] :dmg🔥 [egg=thesovereign] [spoiler=Interesting High Score Tables][url=https://subeta.net/games/battle/scores.php?enemy=206]Paramesian Buttwing Bomber[/URL] [url=https://subeta.net/games/battle/scores.php?enemy=210]Paramesian Recycle Beast[/URL] [/Spoiler][/Center]
The Rules on that Forum were always don't-bother-us. Silly me when I first joined I still thought the folks there meant to be helpful, but mostly they were interested in rigid rules applications or being snobby, or both. They deserve to be ignored. One or two posts sounds about right, good for them.
I learned early on to find a Forum Group or Cult and ask around rather than take up the time anyone there.
I approve strongly of any change to those rules at all.
Actually, these are very good points.
In addition to the rules, I think the general guideline should be "Keep in mind that everyone uses the item pricing board. Please make it helpful and informative for others who research current and historical prices."
The board is intended to ask about unpriced items. But as you said, it doesn't really offer a satisfactory place to ask about trends in pricing, but yet still allows quotes for new items with trivial rarity and usage (which isn't informative). I can see that they don't want open threads hanging around, but there are legit reasons to ask about past trends that simply can't be done because the item's buyable.
Another different thing that's important is keeping factual claims. This is not the same as an opinion, which people have their justification on the valuation of items. I understand it can be challenging to remember what an item has bought and sold for in the past, and it's usually done by an approximating and range. However, when something has changed hands around the time of posting (when participants are fully aware of it), making fictional prices or sales up really hurts the credibility of the board. So, for example if someone ended up quick selling something, please just say it was quick sold. There's no obligation to give a price. I mean if the posters wanted the facts, then why make things up?
Here is another example, where the OP got their answer, but there was still some debate that got shut down:
[Center] [tp=thesovereign] :dmg🔥 [tot=thesovereign] :dmg🔥 [egg=thesovereign] [spoiler=Interesting High Score Tables][url=https://subeta.net/games/battle/scores.php?enemy=206]Paramesian Buttwing Bomber[/URL] [url=https://subeta.net/games/battle/scores.php?enemy=210]Paramesian Recycle Beast[/URL] [/Spoiler][/Center]
I definitely agree with all of these points with the rules.
The other one I find annoying is that if someone lists a price in trades, you can't make a board to see if that's valid/reasonable. So if I have the only Baal for sale and list it at 10B, no one would be able to price-check it with a board because I "priced" mine. Even though that is a rather ridiculous price that no one should pay. xD

Not sure if anyone brought this to your attention, probably would have have been a good idea in the OP :P
Here is another example of where the rules are about to do something somewhat dumb:
[Center] [tp=thesovereign] :dmg🔥 [tot=thesovereign] :dmg🔥 [egg=thesovereign] [spoiler=Interesting High Score Tables][url=https://subeta.net/games/battle/scores.php?enemy=206]Paramesian Buttwing Bomber[/URL] [url=https://subeta.net/games/battle/scores.php?enemy=210]Paramesian Recycle Beast[/URL] [/Spoiler][/Center]