The script is almost fine bar one thing: you never update Old - Current value. Instead of Old, pipe in the Block’s transform translation X. Interp needs an up-to-date sample of what happened last.
And if you must have something like a Timeline in a widget, you can use widget animation and treat its progress as alpha. Repeater events produce an update every frame. But it does not seem necessary here if you’re happy with the widget ticking.