6 sales on mp that are in date

sale 1.

July 25h

sold at 27 usd

keys that day 1.72 usd

27/1.72 = 15.69 keys

rounded to 16 flat

sale 2.

July 24th

sold at 27 usd

keys that day 1.7 usd

27/1.72 = 15.88 keys

rounded to 16 key

sale 3.

July 13th

sold at 27 usd

keys that day 1.69 usd

27/1.69 =15.97 keys

rounded to 16

sale 4.

Jun 18th

sold at 27 usd

keys that day 1.64

27/1.64 = 16.46 keys

rounded to 16 keys

sale 5.

Jun 10th

sold at 27 usd

keys that day 1.65 usd

27/1.65 = 16.36 keys

rounded to 16 keys

sale 6

May 27th

sold at 27 usd

keys that day 1.67 usd

27/1.67 = 16.16 keys

rounded to 16 keys

you have yours listed for 13 but using a range of 10-18

your listing would cap sales at 13

listings: https://imgur.com/a/6IbQuEI

doesn't show 13 keys on the compare link but with what it does show you would need to do a mini for it to explain how you got there

the item history you provided has more movements and possible sales you need to look into

here are other movements to look into

https://backpack.tf/item/13318266633

https://backpack.tf/item/13300472470

https://backpack.tf/item/13284492681

https://backpack.tf/item/13262543900

https://backpack.tf/item/13251471015

https://backpack.tf/item/13251471015

https://backpack.tf/item/13240132406

https://backpack.tf/item/13615989630

https://backpack.tf/item/13450408450

https://backpack.tf/item/13328379761

lastly listings can't be used for ranges only sales

heres something to help you with this

https://forums.backpack.tf/topic/79020-guide-how-to-make-an-unusual-price-suggestion-2021-edition/