You have officially crossed the 10 property barrier and with ease it seems.  

I did a bunch of flips, never made less than $50k on them (I didn't count my hours then!)

So if the most you can borrower is 80k you're looking at 80K x 6% 12 = $400  The lender will count the $400 against your DTI  Obviously if your interest rate is less or more the payment will move up or down.I hope this helps.

It’s to easy you should love sending receipts it’s like counting  your $$$

For the DTI calculation, if net rental income is positive, it counts toward income and improves your DTI. 

Typically the more mailers you send the cheaper the cost, so the pricing really depends on your lead list count.

@Rich Thomas  I count SSI income when determining if a tenant's income qualifies. 

With counting in a ready to rent, 500 square foot additional unit than can be rented for $1,500+ /mo, how much value would this add to the property for the ARV when flipped?

In business, unlike first grade, you can count any way you like: AH4RP One, LLC; AH4RP Three, LLC; AH4RP Four, LLC; AH4RP Five, LLC; AH4RP Nine, LLC (see image below of NCSOS search results starting with 'american homes'...

Your parents can even cosign for you and you can count the anticipated rents towards you income if you by a multifamily unit.