static c/r is more than just the compression stroke. The EXPANSION ratio is what contributes a significant amount to the increase in power / efficiency of a high compression engine (although you could probably get away with a slightly higher c/r in a miller engine). The miller cycle does nothing to increase the expansion ratio, and adds cost + complexity. The basic idea behind the miller cycle is, the first X amount of degrees from BDC is the least efficient at compression due to lack of mechanical leverage, so delay the compression stroke X amount of degrees and let some of the intake charge revert back out of the intake valve. In the Mellenia's case, it has the internal friction of a 3L, with the tq of a 2.3. Also remember that engine runs a lysolm twin screw supercharger which is very expensive.

If the c/r sweep is large enough for this motor, and it can stay in the optimal c/r at each load point, it will produce significantly higher efficiency #'s than a miller.