Hashes don't work this way. Each key must be and will be unique. No way around it. So what you are doing is setting $foo{one} to 1.2 ...and then to 1.6 ...and finally to 1.9

Tie::IxHash only preserves the order that the hash elements were created. It does not over-ride the one-value-per-key characteristic of hashes.

You cannot do what you are trying to do with hashes. Perhaps if you told us more about the problem you are trying to solve, we could suggest some ways to address it.

And when you have a some time, take a look at the section of perlvar that deals with hashes. They are a rich and wonderful tool when used as intended.

HTH, David