Corner bass traps - most installed wrong?

I have a corner base trap thats 4 feet high. My ceiling is 8 feet. Shouldnt I extend the bass trap up to the ceiling? I got my bass trap from Ats acoustics, seems well built, was only about $200. Could I do better and why?

Most well-designed listening room’s i see only install them halfway up. So why do they do this? Are they wrong? bass waves affect the entire corner area so do I need to increase the height?

I’m only doing one corner, probably should do more.