As I recall, Hussmann's Koolsurge showed up in the 1980's with the Plus System racks. It was supposed to work like Hill's Attron system to control either flow though or surge receiver operation for low ambients. Hussmann later came up with Autosurge for the SuperPlus.
I may still have some old info on Koolsurge at the shop. I'll have to dig for it.
I looked up the Attron on this site, there was alot of good information on them. I think what I have is different in that the drop leg is not attached to the liquid header but goes into the top of the reciever,I will look when I go back out. If the drop leg does go into the reciever then I would not need this controler to pressurize the reciever to force the refrigerant out. Am I thinking right.