Retargeting while copying transform [ UEFN-Attach / Manny-Interaction ]

I have 2 skeletons, specifically the UEFN one and the SKM_Manny one, and I’m trying to retarget between them.

I used the automatic one, but I need to also re-target the attach bone, doesn’t matter to where.
In order to make it simple, I decided to retarget it to the interaction bone.

The idea is to simply copy the translation changes, since that is all the attach bone has.

I tried to create 2 chains, and then set interaction setting to include FK, Rotation mode None, translation mode Absolute, translation alpha 1.0, but the translation still isn’t copied exactly - the values are simply incorrect.

What am I missing? how can I do that?