Originally Posted by
WhyFi
I think that it's fairly common to have imbalance at different outputs or fatigue levels, as well; for instance, someone with a 50/50 balance at tempo may be 42/58 at sprint outputs, etc, so even a blanket adjustment may not tell the whole story. As always, though, whether or not that's important depends on what you intend to do with that info.
I think the balance is usually reversed. You might see 45/55 for zone 2 but I think most people get much closer to 50/50 once they go above tempo.