I think there's a much larger correlation to the smoothness of the DI. Large steps, bumps, dips, etc, (or the lack thereof) are going to be more of a determining factor than how high or low the curve is.
I wouldn't jump to broad conclusions over that test. Those were two of the very highest testing speakers around--the test was somewhat splitting hairs. Like a test between a high end Ferrari and a high end Porsche. If the Porsche wins a particular test, it may be unwise to jump to the conclusion that "rear engine is better" and go shopping for a VW Bug for the performance advantages of that design.