Marketplace.tf sales:

https://marketplace.tf/items/tf2/1111;5;u3010

$11.99 / $1.98 = 6.06 keys - high

$13.99 / $1.99 = 7.03 keys - high

$7.66 / $1.98 = 3.87 keys - low

$6.25 / $1.92 = 3.26 keys - low

$9.59 / $1.87 = 5.13 keys

$9.59 / $1.80 = 5.33 keys - high

$9.59 / $1.79 = 5.36 - high

When using bot.tf stats for unusuals, you can only use a price point when there are 3 or more sales at that price. In this case, as there are 4 at 5 keys and 6 at 4 keys 15 ref, this should be fine. In cases where there are less, you need to trace those sales to guarantee they sold for that price.

One mistake here though, 4 keys 15 ref is 4.3 keys, not 4.5. With the additional 5.13 sale from marketplace.tf, I would re-suggest at 4.3 - 5.15 keys.