Ok sorry, so it seems that this works only in canada or anywhere KPH is used. I could not try this in the US yet but it seems that it has the opposite effect in the US . Here is a video link I just uploaded.
Speed limit is 30 KPH units set to KPH. AP limit is 30KPH. Units changed to MPH. Limit increases to 30MPH which is 48KPH.
Speed limit is 30 KPH units set to KPH. AP limit is 30KPH. Units changed to MPH. Limit increases to 30MPH which is 48KPH.