You cannot pull a range from nowhere.

https://backpack.tf/profiles/76561198072999396#!/compare/1672444800/1672790400

https://backpack.tf/profiles/76561198054198170#!/compare/1672704000/1672790400

This sale for the Burning Flamenco was for the Cloudy Anger, can't really be used right now for either

So you could take the Flamenco at 400 keys outdated https://backpack.tf/suggestion/63234c48ff0fedcded02bd2c, as you've done here

Vivid HKC is going to end up a little higher,

https://gladiator.tf/time-machine?item=Vivid%20Plasma%20Hong%20Kong%20Cone&at=2023-01-26T09:07:53.000Z

https://backpack.tf/item/8619762903

~87 key buy order

https://backpack.tf/profiles/76561198399223587#!/compare/1669593600/1669939200

https://backpack.tf/profiles/76561198851597200#!/compare/1669852800/1669939200

https://gladiator.tf/time-machine?item=Vivid%20Plasma%20Hong%20Kong%20Cone&at=2022-12-02T14:37:00.000Z

1:1 w/ Starstorm Slumber Modest Pile of Hat probably (outdated 89), other sale was with the Kazotsky https://backpack.tf/profiles/76561198851597200#!/compare/1668729600/1668816000

https://marketplace.tf/items/tf2/30177;5;u16

https://manic.tf/keyprice/?at=2023-01-15&price=229.99

$229.99 / $2.00 = 115.00 keys, a little high given sellers

So you could take 88 for the HKC here, giving a total of 400 + 88 = 488 keys, this can be rounded up to 490 keys. So a flat value of 490 keys might work for now. A range in this case is never allowed unfortunately.

as mentioned by other users already, you shouldn't be creating a range from a single sale. mini's are required on the outdated items involved to give them an updated estimation based off recent sales that reflect it's current value