http://forums.backpack.tf/index.php?/topic/6033-guide-for-unusual-price-suggestions/

Sales older than 2 months old are not valid proof; this does not mean that they are not useful. Feel free to include them to provide supplemental proof. Just don't rely on them to set your range.

Exceptions: 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.

4 usable sales,2 pure sales are newer and higher. you were saying ?

edit: and yea,i'd counter for a 0.5 difference.