Question about the 1% Rule

Hi all

I have a question about Steves 1% Rule in his book. I am at the moment at the very begining of my self educating process of investing and am just having fun looking at rental incomes against property prices.

My question is using Steves 1% rule, if I have the 20% deposit for a property should I be changing the maths from annual rent devided by asking price x 100      to annual rent devided by 80% of asking price x 100 to work out if a property has the potential to have a positive cashflow.

Thank you in advance