You have the wrong compare links for Sale 2. The sale was for a Field-Tested Isotope Skull Study Flame Thrower

https://backpack.tf/profiles/76561197994697258#!/compare/1607212800/1607299200

The Flame has no sales, so you can use this to price that.

You also have the wrong compare links for Sale 3. That sale was a quicksell for 26 Keys + 13.66 Refined, which will be too low.

https://backpack.tf/profiles/76561198048392996#!/compare/1607731200/1607990400

You also have the wrong compare link for the Buyer in Sale 4. The 10 Keys + Aloha Apparel + Handsome Devil match on the Seller's side.

Sale 4 looks to be the Max's Head + 10 Keys + ~4 Keys of Items (S. Spec Sticky + S. Spec Grenade + Aloha Apparel + Handsome Devil + Festive Targe)

https://backpack.tf/profiles/76561198079804514#!/compare/1608076800/1608422400

That makes Sale 4 equal to 20 + 10 + 4 = 34 Keys, so that'll still fit in the range here.

As a note for future suggestions, the correct compare link should have the item you're pricing in it (Removed for the Seller and Added for the Buyer).

Sometimes it won't show when comparing between both a day before the sale and after, in which case 99% of the time comparing the date of the sale with one day before it will yield the correct compare link.