Is Ultimate Hat / Cosmic Insight worth? - A look into CDR

Have you ever wondered if Ultimate Hat is even doing anything? Or what champions are most efficient with the extra 5% CDR from Summoner's Insight! Well wonder no more!

For some insane reason, I calculated the cooldowns of every champion's ult (as of 8.2), including buff and pet durations, to give you all a comparative show of what you get out of 5% CDR.

https://docs.google.com/spreadsheets/d/1utktFOPI-k8GR5E7MeCuICc4GJnOm_JGR5THIgr_1nI/edit?usp=sharing

So you decide. Is it worth getting the 2 sec off Lux's ult, or the 9 sec charge time on Teemo's shrooms? Here's the numbers, discuss the implications!