The non-strange version is 11-12, the strange versions are normally at least 1 key higher

You missed many other sales.

Cloud 9 Oiled Baker (mini at 15)

https://backpack.tf/profiles/76561198018613073#!/compare/1501632000/1501891200

https://backpack.tf/profiles/76561198309371123#!/compare/1501804800/1501891200

The Baker sold for a Spectral Swirl Battin (16.5, but seller at 15) here:

https://backpack.tf/profiles/76561198309371123#!/compare/1501459200/1501545600

Sold with something for a Cloud 9 Cannonball (28)

https://backpack.tf/profiles/76561198309371123#!/compare/1501891200/1501977600

https://backpack.tf/profiles/76561198144599511#!/compare/1501891200/1501977600

Sold with 2 keys for an Abduction HFoHA (outdated at 22.5)? ----- Probably something else involved, not using.

https://backpack.tf/profiles/76561197998145090#!/compare/1501891200/1501977600

https://backpack.tf/profiles/76561198309371123#!/compare/1501891200/1501977600

(quick)Sold for 13 keys in 2 days

https://backpack.tf/profiles/76561197998145090#!/compare/1502236800/1502323200

https://backpack.tf/profiles/76561198153033788#!/compare/1501804800/1502323200

Histories don't match

https://backpack.tf/profiles/76561198153033788#!/compare/1502323200/1502496000

https://backpack.tf/profiles/76561198171841681#!/compare/1502409600/1502496000

???

https://backpack.tf/profiles/76561198171841681#!/compare/1502409600/1502496000

https://backpack.tf/profiles/76561198172423706#!/compare/1502409600/1502496000

Sales that happened after you made the suggestion:

Quicksold for 10 keys

https://backpack.tf/profiles/76561198296062531#!/compare/1503100800/1503187200

https://backpack.tf/profiles/76561198260833001#!/compare/1502496000/1503187200

Quicksold for ~8 keys ----- Countered by buyers

https://backpack.tf/profiles/76561198204433501#!/compare/1503014400/1503100800

So there are sales at 10 (pure), 12 (pure), 13 (pure), 15. Current seller at 12.

It's fair to ignore one sale in both ends, so you should resuggest at 12-13.