Multiple function in one script for new UI Button

Hi there,

I am facing a brick wall right now and trying to understand what is wrong with my script. I have 3 buttons in my scene and I have written one script which holds 3 function that are supposed to be used by each three buttons. But now the funny thing is that only the first button works well, sets everything else active and plays it MovieTexture, but the other button is very slow and ends up not doing what is supposed to do.

Can one explains if I do have to rather write each buttons function in separated scripts or function for the buttons can all be in one script?

It seems as if Unity decides when to have this script work or not. I tried again the same script and suddenly it now works without me making any changes.