First Rental Property - CoC return calculation

[Adam Delort]

Hey guys,

Just curious if you can help me analyze a deal. There is a condo that has been flipped nearby for sale at $78,000. Im going to offer 76,800. Below is my calculation. Is this accurate? 

Second question. there is an option for investors in my area that can get a rental loan with 15% down... This would save me $3,840 off my down payment but add $30 per month up to 20% equity then i can call to have it removed. Im trying to figure out how long it would take to get 20% equity with the 15% down / PMI option and if the CoC return would be greater... How do i calculate that out?

Also is 4% for vacancy and repairs average or should i increase?