I've never seen the T5 in 15-40 around here, but know we don't see all the blends.
Many of us were using Rotella long before it became JASO certified. It worked fine then too.
Good luck with it.
Some people go their whole life wondering if they made a difference, Marines don't have that problem.~ Ronald Reagan
2012 XCT, AFR+ Gen 4, Lloydz air filter. I don't equate noise with power.
I ride with the Force.