I have found a great article on the usage of “heavy” and "super’ in call sign designations. There seems to be a lot of confusion. My understanding after reading this and many more articles. The “heavy” designation is to be used only on aircraft more than 300,000 lbs while the "super designation is to be used only for the AB - A380.
Hope this isn’t duplicate info, but I keep seeing B-737s, A318s, and even a Cessna Citation using the ‘heavy’ and ‘super’ designation.
The article has some great info on the wake turbulence caused by these larger aircraft and how the designations help ATC maintain separation.
Hope this is beneficial to someone and see you in the air!