Am I doing this right? New to deal analysis

Hi there! 
I've been running some deals in a spreadsheet and I'm unsure if I'm doing this right or if I'm missing something. Was hoping some folks here at BP were willing to take a look and give some feedback?

Here's an example of a 6 bed 2 bath multifamily that's now off market but was priced at $599,000:
https://www.zillow.com/homedetails/6-8-Belleview-Ave-Ossining-NY-10562/33076551_zpid/
* Rentometer gave me an avg rent of $2,759 for a 3 bed 1 bath, and this property has two units like this. So I'm using $5,518 for monthly rental income. (Note: Zillow's "Zestimate" is $4,200, but I'm using Rentometer for this particular deal.)
* I'm using 5% of that for maintenance ($276), 5% for vacancy ($276), 5% for cap ex ($276), and 6% for prop mgmt ($331).  
* Zillow had taxes and insurance estimated at $983 and $210 respectively.
* Using mortgage calculator plus, with a 20% down payment ($119,800) and a 30 year fixed rate mortgage at 6.5%, the monthly mortgage payment woud be $3,029.

Using those numbers, this property should cash flow about $137 per month for a 1.3% ROI.

Does this look right to you?
Any other comments or feedback?
Thanks for taking a look!