Therefore, in order to pay off your acquisition loan and get your cash back your costs  need to also be 75% or less.  70% gives you a 5% buffer encase the appraisal comes in low or your Rehab costs are more than expected.  

With a PM you are paying for them to basically be the buffer between you/tenant.

If you'd rather have a bit of a buffer for uncertain times, stay the course or make the occasional extra payment.

Maybe get rid of the 10% buffer if you already have a lot of science behind the estimate.Maintenance - As others have said, the maintenance number is too low (especially for 100% turnover) but your combined maintenance and cap ex do not appear too low.Appreciation and Principal Reduction - Cash flow is one of three profit drivers in real estate and to calculate the true return, factor in the other two drivers using the IRR.At a 60% expense rate for a $1450 rental, you are likely forecasting expenses a little on the high side (even with the higher taxes) but you may not be too far off (and the tweaks I mentioned may help).

This keeps the most amount of your cash on hand to purchase another property, or to use as a buffer for repairs/future renovations/considerations. 

If you want to do a TRUE BRRRR where you get ALL of your cash back you may want to set your criteria as 70% to ARV all in so you have some buffer. 

We're looking to flip houses as well to increase our income, and hopefully bring a respectable downpayment to the table Cosigners are almost definitely out of the questionBoth our credit scores are good (low and mid 700's, with the only thing holding both back being length of credit history)I'll be graduating with about one years salary in student loans, he won't have anyLooking at comps, rental income will be able to cover all PITI expenses leaving behind a buffer of several hundred dollars a month for home repairs.

The total flow for the year will remain the same, but since the vacancy allocation is more of a way to make sure you have a buffer for when there is vacancy rather than an assumption that someone will move every month, it's a more realistic way to look at that expense.I would also consider your PM rate.

I also left a 6 month holding period as a buffer since any deal I do will be my first. 

Are you currently working outside of RE to help buffer in the event of financial crisis?