Can't store float value over time.

Hello! I am absolute novice to Blueprints and Unreal in general. I tried to play “CameraFocusSound” whenever there is a noticeable change in vector float. To do that I need to store a “Last FrameVectorValueVariable” over a certain period of time to then compare it to a new vector value. With this poor setup I can’t store the float value.

This is the demo for Zoom in-out sound,but there is no sound for adjusting focus:…

What am I doing wrong? Thank you!