Why would Loan Officers say this?

[Matt Maluchnik]

I just met with a bank VP of a local (smaller) bank. They mentioned that even though I'm interested in single family homes for investing... They are all considered 'commercial' investments and would require 20% down with it being spread out over 20 years. However, when I was watching one of the Bigger Pockets videos it said anything under 4 units was able to be a 30 year loan. Can anyone explain the difference in what's said? It Changes my numbers when using rental calculator.