The problem is that those aren't actual sales. They're merely the price it was listed for during the time of the sale.

https://gladiator.tf/sales?item=Vivid%20Plasma%20Reel%20Fly%20Hat&at=2023-02-02T18:04:24.293Z

See bottom page: ''These statistics show what the bot's listing was at the time the item was bought/sold. This is not a guarantee the item was bought/sold at this price - the user could have overpaid, underpaid or used items to trade instead of pure''

Generally it is likely it sold for X amount if some keys match and there's no indicator of anything else being involved; but with zero compare links or zeor keys matching anywhere we can't assume it sold for 18.