Is this Rental analysis Cash-on-Cash Return good enough to convince investors to join your team???

[Dee Xixi]

I am writing a business plan to send out to couple investors. Here is the financial projection and my selling point to them.
Please criticized and reveal any flaws of my analysis.

6 -12 units that can be purchase for 520k of under. The amount 520k represents 65% of market value of properties recent sold in the past 6 months. I will be interested in 2 bedrooms and up.
Purchase Price: $520,000 using the high value
Down payment: $ 104,000 -------20% down from an investor
Improvements: $50,000 represents 10% of purchase price -------- Improvements technological amenities- energy efficient appliances- some remodeling.
Closing: 570,000 x 2% = 11,400
Total: 581,400 ARV --------- Represent 72% of current market value.
Finance Amount: 581,400-104,000 = 477,400
Interest Rate @ 8%
Mortgage years: 360 months
Mortgage Payment: $3503

Revenues:
Let’s assuming each unit rent for the minimum rent in the area. For 1 bedroom (900-1150); for 2 bedroom (1050-1350) and for 3 bedroom (1200-2100). Let say for a 6 unit’s apartment, 3 of the units 2 bedrooms and the other 3 are 1 unit.
For the 1 unit; 3 x 900= 2700
For the 2 units; 3x 1050= 3150
Other income from storage, wireless, laundry and water = $1000 @ 200 person
Rental income: 4,800 monthly for 5 units and one 2 bedroom unit vacant.
Gross rental income: 5,800 monthly and 69,600 yearly.

Expenses:
• Property Taxes : 8,000 ------ use the highest number
• Insurance : 4,000 ----------- use the highest number
• Maintenance ----------5,000
• Management @ 6% of rent -------------------------------- $3,456
• Advertising (to advertise for tenants) --------------------- $ 500
• Utilities ------------------------------------------------------ $pay by tenants
• Other (anything else we may have missed above) ------ $1,000
Total: 16,956
NOI
69,600 – 16,956 = 52,644
Cash Flow
52,644-42,036 = 10,608
Cash-on-Cash Return
10,608 /104,000 = 10.2%
The investor makes $ 10,608 yearly for at least 5 years plus the original investment at the end. When I refinance.