Sale 1:

https://backpack.tf/profiles/76561198423200755#!/compare/1587513600/1587600000

https://backpack.tf/profiles/76561198205612720#!/compare/1587513600/1587600000

Sold with 1 key for Smoking Pillar(12)

Total is 11 keys

https://bot.tf/stats/listings/M0ONP672

B/O of 12 keys

sale 2:

https://backpack.tf/profiles/76561198205612720#!/compare/1588032000/1588204800

https://backpack.tf/profiles/76561198253316756#!/compare/1587686400/1588291200

Sold for ~10 keys

sale 3:

https://backpack.tf/profiles/76561198253316756#!/compare/1588291200/1588464000

https://backpack.tf/profiles/76561198360120859#!/compare/1590105600/1591228800

Sold for ~8 keys in sweets

sale 4:

https://backpack.tf/profiles/76561198360120859#!/compare/1590105600/1591228800

https://backpack.tf/profiles/76561198163522694#!/compare/1591228800/1591315200

Untrace

sale 5:

https://backpack.tf/profiles/76561198205723668#!/compare/1585526400/1586822400

https://backpack.tf/profiles/76561198254882979#!/compare/1586736000/1586822400

Sold for 12 keys

sale 6:

https://backpack.tf/profiles/76561198254882979#!/compare/1587945600/1588032000

https://backpack.tf/profiles/76561198129995083#!/compare/1587945600/1588032000

Bulk

sale 7:

https://backpack.tf/profiles/76561198129995083#!/compare/1591747200/1591833600

https://backpack.tf/profiles/76561198024867201#!/compare/1591747200/1591833600

QS

sale 8:

https://backpack.tf/profiles/76561198149097275#!/compare/1592006400/1592179200

https://backpack.tf/profiles/76561198098849547#!/compare/1592092800/1592179200

https://backpack.tf/profiles/76561198106112825#!/compare/1592092800/1592179200

Untrace

sale 9:

https://backpack.tf/profiles/76561198106112825#!/compare/1592092800/1592179200

https://backpack.tf/profiles/76561198242646048#!/compare/1592092800/1592179200

Sold for Steaming Merryweather + 1 key

use there

https://bot.tf/stats/listings/4O9XJXDQ

B/O of 12 keys

sale 10:

https://backpack.tf/profiles/76561198242646048#!/compare/1592179200/1592265600

https://backpack.tf/profiles/76561198284570728#!/compare/1592179200/1592265600

Bulk

sale 11:

https://backpack.tf/profiles/76561198284570728#!/compare/1592179200/1592265600

https://backpack.tf/profiles/76561198092554004#!/compare/1592265600/1592438400

Sold for ~13 keys

sale 12:

https://marketplace.tf/items/tf2/120;5;u18

$30 / $1.88 = 15.96 keys

Total sales @:

8, 10, 11, 12, 13, 16 keys

buyers up to ~10 keys,

seller at 15 keys,

https://bot.tf/stats/listings/MLVXLQNZ

previously listed at 14 keys,

https://bot.tf/stats/listings/MGLR3LN7

raised to 16, then dropped to 15.

given seller and sale 16,

taking 11 - 13 keys.