While I usually agree with the idea that the next generation is about 1 1/2 steps up from the previous, which means that the Gen 6 Plus should sound a little better than the Gen 5 Super, at least in some ways, I find that each tier has a somewhat different sound profile from other tiers. For example, the Super tier tends to have a strong bass emphasis and the Ultra tier has a less forward bass, but is much better controlled.
An important factor is component compatibility. I have experienced a couple of systems (not mine) that worked better with the mm1 generation interconnects than they did with the mm2 interconnects. However, as one of those systems evolved, the mm2 cables became preferable.
In my own system I found that the power cord choice for my amp was better with a one step higher tier but, one generation older power cord which was the Powerlink mm2 (the higher tier, older generation) vs. the Reference Gen 5. Also, I prefer my dac to have a Gen 5 Premium power cord instead of a Gen 5 Reference cord. Again, it comes down to the sound profile of each tier.
This whole thing about having different sound profiles for the various tiers is a controversial matter. Some people disagree with the whole concept and others like the idea of tailoring the sound of their system to their personal preferences and finding the best compatibility for each component, especially with power cords.
So, there is no cut and dried answer for every case. You need to do as much trial and error testing you can.
