A 580 is a 580, a 480 is a 480. The 580C wasn't reincarnated into the smaller size tractor. The 580C was revamped to a 580D.
580's were all 14' class backhoes
480's were all 12' class backhoes, then later they added the optional 14' hoe for the 480D, 480E,480F. It was the same exact dipper, but with just a longer boom portion. All of the 480's had a single right side mount boom cylinder.
All of the 580's from B-E had twin cylinder over center boom design, they were all 14' class standard hoes. With optional 14'-18' hydraulic telescoping extendahoe as a second choice.
The 580C had a 55hp 207cui Engine. The first series of the D's were the same exact specs as far as loader and hoe goes, except with improved hydraulic performance, and of course some other upgraded features were the cab, red button on loader lever etc.
But there was no reincarnation of the 580C going down a size in tractors.
A 480 was always a 480, a 580 is always a 580. sure they revamped the line, but that is where the similarities end.