CapEx Projections Question

[Matt Maluchnik]

I grabbed these numbers from 'The Millionaire Real Estate Investor' book. I've been adjusting the LifeSpan based on the situation. For example, If the roof was put on 10 years ago, I would change from 25 to 15...ect. I normally still end up with numbers around $175-$200 for the total per month. SO, when I go to use the Rental Calculator Tool...a lot of times this ends up being a CapEx % of around 20%. So I'll usually have Vacancy 5%, Repairs 5%, CapEx 20%, and Management of 10% . Am I doing this correctly?