If it is an Option 11C Cabinet or Chassis system upgraded to a CS1000E, Cabinet 0 becomes Loop 0 Shelf 0, Cabinet 1 is Loop 0 Shelf 1, Cabinet 2 is Loop 4 Shelf 0, Cabinet 3 is Loop 4 Shelf 1 and Cabinet 4 is Loop 8 shelf 0.
If it is a CS1000S upgraded to CS1000E it starts with MG 1 being Loop...