UI size is different on my toons

First, let me say this. i just was in contact with a customer support rep on chat. He basicly told me that the issue I was having does not exist and is not possible. He refused to let me explain the steps i was going though that were a part of this unending loop. It was the worst contact with a customer support rep i have ever had in all of the mmos I have played. Thus I have to come to the forums and seek help from others for my problem. Forgive me for my little rant, and here is my problem. I made a video of my problem and hope that people can get to it but I'll explain everything here as well. On one of my toons all of the icons are too small. i go to system, display settings and change it from 100% to 150%. The icons are back to normal now. I then log into my main and now the icons are HUGE! I go back and set it back to 100% which fixes the main toons problem but now my alt is back to being too small. It is a never ending loop cause of this. He said the UI was per toon and that this unending loop is impossible. Please help! Video link: https://youtu.be/KRjn92CNKzY

You can set UI size individually by going into UI Layout menu, select UI element(s) and then press button to enlarge it until it loop back to small version (I think it's Ctrl + Home on keyboard, not sure about conroller. Sorry about that).