01-21-2016, 11:23 AM
I spoke to someone from Castrol and the figures for both GTX HM 20W50 and SAE40 are lower:
Castrol SAE 40 = 0.11% (1100 ppm)
Castrol GTX High Mileage 20W50 = 0.10% (1000 ppm)
Castrol SAE 40 = 0.11% (1100 ppm)
Castrol GTX High Mileage 20W50 = 0.10% (1000 ppm)