Once again we need to stop looking at defenses on paper as being "better defensively". That's just not how it works. It's all part of the same scheme to score more than you allow. It doesn't really matter if your defense surrenders more high danger chances if they also work together w/ the rest of the team to generate more possession, shots, and goals.
To put it another way, the Flames were already in the top-5 for fewest scoring chances and high danger chances against last year. It didn't help them because, untalented and stifled by coaching, they don't convert as much as their opponents do.