for starters, you can’t use Mannco.store sales anymore, and plus, simply listing current listings/sellers isn’t valid. They must be recorded and documented sales.

sales on both mannco and marketplace are out of date. where is the range coming from and what key price are you using? also your backpack link is just a link to the classifieds for the item, there's no sales history there.

https://forums.backpack.tf/topic/6033-rules-for-unusual-price-suggestions/

Our price moderators have no access to Mannco anymore, and along with the recent changes that do not allow the viewing of their sales graphs without logging in, we are no longer able to verify Mannco sales. Unfortunately, that means we can no longer allow trades that occur on Mannco for price suggestions

For very rare hats, if there have only been 1-2 sales in the last 3 months, a trade up to 3 months old is okay to use as proof to establish more data points. Keep in mind, new sales should take precedence over older ones.

Use the value of keys on the site at which the item sold to determine the key conversion at the time of the trade. (i.e. use the SCM value of keys on SCM sales, use the marketplace.tf value of keys on marketplace.tf sales, use the opskins value of keys on opskins sales). For most transactions, this means you can use the key value at the exact date of the sale.