My sis just bought a Malibu Maxx. The manual says to use any oil that meets GM 6094. I was thinking that this would be a great place to start using some of the AA .34 stash of Hav Syn blend, but looking at the Texaco website, the Hav conventional, and the Hav synthetic both meet the GM spec, but the syn blend does not. Does anyone have an opinion, or info why the 2 oils mentioned do meet the spec, but the probable combination of the 2 doesn't? Maybe they just didn't pay for the certification?