To recap what we explained lower down in the comments:
- The originally is extremely forced and only uses that number of stairs because it's the only number pairing that does what the author needs it to do.
- If the characters had been wheezing and panting, yes, we would have not done this change, however, there was zero emphasis on it at all.
- Thus, we concluded that the actual number was not important and that the author only chose it to brute-force his meaning. Therefore, the most important thing in this text was the meaning.
- However, we included the original anyway in a TL note so that people who prefer things that way so can enjoy that as well. For any changes such as what we did in this chapter, (see: the beach swimming chapter), we always add a note so that people can enjoy both a smooth reading experience that matches how a native speaker would experience it, and people who care about the exact original can see and know that as well.
- This number, unlike the localizations of 4Kids, is not changing the culture of the original. For cultural items, we always remain faithful (see: Acchi-Muite-Hoi chapter). This number has absolutely nothing to do with Japanese culture and was made up by the author for a specific purpose.
- Either way, we cannot please everyone. (also: Acchi-Muite-Hoi, not all of the complaints are on MDex, but we got quite a few complaints for leaving it as-is). All we can do is weigh each option carefully and do what we can to select we think will not detract from the flow of the reading experience.