You know why PUP didn't get Cure VI?
Because it literally does not need it.
Look at the WHM forums. Cure VI heals the same as Cure V, but costs more MP. The only reason to use it is because it generates even less enmity than Cure V.
Automatons Cures generate no hate to begin with, therefore Cure VI would be absolutely useless, and actually a debilitating spell for automatons to have. Waste of MP.