I wish i could get HDEO for the prices you get it over in the US....
For Rimula R4X 15W-40, which would be a rough equivalent of Rotella T4 15W-40 i pay 26€ for a 5L jug at the cheapest. , which comes out to about 22$ for a US Gallon ( 3.7L ) of oil.
What IS interesting though is that the Rimula R4X which is a rough equivalent of the Rotella T4 in the US, is still APICI-4 / SL, although it meets ACEA E7 and other specs.
Don't get me wrong i like that, what i look for in a HDEO is lots of TBN, sulphated ash and Zinc, and CI-4 gives me that.