That was what Mobil told me. It was also tested on PQIA, and I think Amsoil. Also the Russian Oil club.
Take for example EP 0w20 and ESP 0w20:
"The main difference between the two is the ZDDP content. ACEA C5 requires a 700 ppm phosphorus minimum, whereas the non-Euro Mobil 1 0W-XX varieties (excluding high-mileage and racing) are for some reason (to decrease the coefficient of friction and improve the fuel economy?) skimpy on ZDPP with 650 ppm phosphorus. M1 ESP x2 0W-20 probably has 800 ppm phosphorus, which would be 23% higher than the non-Euro M1 0W-XX oils'. The other difference is the VII content. M1 ESP x2 0W-20 has a lower VII content, which is typical of ACEA C5 0W-20 oils, which are more focused on reducing wear than improving the fuel economy. They also tend to have a thicker base oil but M1 ESP x2 0W-20 doesn't have a particularly thick base oil for a 0W-20. However, M1 EP 0W-20 has a PAO base oil and probably more antioxidant, which should allow longer OCI's than M1 ESP x2 0W-20. The final difference is in the lubricity base stock. Non-Euro M1 varieties use Group V alkylated naphthalene (AN) as the lubricity base stock, whereas Euro (ESP and FS) varieties use Group V polyol ester (POE). While POE cleans better than AN, which may perhaps be useful for the European passenger-car diesel engines, it increases the engine wear as it competes with the AW/EP/FM additives, but for the 5-7% POE content used in the Euro M1 oils, the effect is small. Given the price and availability, I think to go with M1 EP 0W-20 is no-brainer."