And therein lies the problem with even an objective EN rating system.
There's an uncontrollable variable, and it is US!
People seem to look at that rating and ignore the specified layers and pad r value, AND the additional fact that both the testing for r-values and EN ratings are arrived at using heated plates and heated mannequins, respectively.
If you don't put out as much heat as those standardized heat sources, your pad's r value drops, and your insulation doesn't have as much heat to keep in, so can't match its rating.
If you put out more, that r value goes up, and those EN limits go down.
That doesn't mean there's anything wrong with you, or wrong with your gear. Some of us just sleep warmer or colder, and need more or less insulation.
But you have to find out firsthand, through personal experience. You might get some useful suggestions, but some other person on the internet can't answer these questions for you.
I've got a good friend I've backpacked with a few times, now, including some short winter stuff. He sleeps about 10F cooler than average, while I run 15-20F hotter than average. That is a HUGE difference. Rest assured, neither of us is giving the other advice about which pad or bag to bring!
Sleeping hot is kinda awesome, though. Let's you carry less weight and bulk. And maybe pick at someone now and then