Interesting. I live at low altitudes and I almost always have to cook noodles longer than the instructions on the box. Now I only use Italian pasta like DeCecco or Rummo.
Yeah, I think usually the recommended time is an underestimate for me, but it depends strongly on the brand and type of pasta. I usually treat the recommended time as a ballpark of when to think about monitoring it closely if I'm busy prepping other things. Usually the first time I cook a given type of a given brand I'll watch it more closely and then try to remember what seemed best.
I am the same though I'm embarrassed to admit I never realized it was because I'm at sea level. I just always wondered what was wrong with pretty much every printed pasta cook time. Doh.