What sale is considered a quicksell?

[Sharp Volcano Fragment]

So i’m thinking of making an unusual suggestion but I don’t know what type of sale counts as a quicksell. I read the  rules and I still can’t understand 

[TheTexanTiger]

If a sale is far below the range of multiple other sales, or is below the current asking price (buyer's price), then I would consider it a quicksell. 

For example, if you have a hat with sales in the past 3 months of 44 keys, 60 keys, 65 keys, and 72 keys, the best range would likely be 60-72, as 44 was likely a quicksell.

It's very subjective, however, and there's no set rule for what constitutes a quicksell.

[`Yahiamice]

Additionally (i'm not sure if these rules are still in effect), but if a hat's sold for it's buyout price within a week of it being listed, chances are it's probably a quicksell; regardless of whether or not the trade text actually labelled it as such.