Rotella is a North American brand. Rimula is their big brand from Europe. Shell US introduced a cheaper, lower performance (yet decent) CI-4 Plus alternative to Rotella here in the US a few years ago. The performance difference between the two was easily seen comparing CI-4 Plus formulations (though Shell is on it's 3rd CI-4 Plus Rimula formulation since introducing it a few years ago - why they used 3 different formulas all meeting the same CI-4 Plus spec is puzzling to me). The performance difference between CJ-4 cheaper (fleet grade) and premium products is not easily determined by looking at a PDS like it was for CI-4 Plus oils; it's practically camouflaged now leaving marketing and, if you can find it, more detailed test data to highlight differences. The are indeed significant differences when you look at the data.