New sale:

Sold for 4 Keys and 17 Ref

https://backpack.tf/profiles/76561198013218608#!/compare/1760832000/1761004800

https://backpack.tf/profiles/76561198316831771#!/compare/1760745600/1760832000

As per rounding rules, this rounds down to 4 Keys.

These sales are far too discrepant. Given this listing was up for some time, it indicates that 7.5 is too high as of right now.

This will have to stay outdated. I'll close this as you seem to have a tendency to ignore mod comments, hopefully you can prove me wrong in the future!