> So I don't think it's incorrect to call a price list a "tariff"
I'm pretty sure it is in American English. That usage might be ok in British English, but for Americans that terminology is going to be confusing. Before today, I had never heard tariff used for anything other than import taxes. And since this applies to servers in the US, it would make sense not to use terminology that would be confusing to people in that country.
From what I can tell, in the US energy suppliers talking to one another use the term "tariff" like for example https://www.puc.texas.gov/industry/electric/rates/tdr.aspx
Whereas when talking to consumers they seem to use terms like 'rate' and 'plan'.