https://backpack.tf/help/suggestions

Please remember that common trade points are defined by completed sales - not buyers or sellers.

1 sale = 1 price

2 sales at different prices = range

classified listings can't be used for price suggestions

you showed a transaction for 80 keys then the price should be 80 keys flat

also compare link only shows 79 keys so this should be 79 keys unless you can provide a screenshot of the trade

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