DTI Issue: House Hacked Rentals to Purchase SF Primary

[Dillon O.]

Looking for advice on how to navigate this unexpected scenario.

My wife and I own 2 duplexs we acquired with owner occupied financing and house hacked/fixed up. Both are in our personal name. Living in the 4th unit right now and renting out the other 3 (that we already lived in and fixed up). We would now like to purchase a single family home and rent out the 4th unit we currently occupy.

The issue is, the lendor I spoke with is saying our DTI is maxed out hindering us from qualifying for a SF primary mortgage. Im a bit confused by this as the numbers im running seem to pan out and shouldnt cap us.

Here is the math:

Property "A" (side by side duplex) valued at $580K with 38% equity (owe $360K) on a 30 year fixed conventional with 2.8% Int rate - PITI: $2800/ month. Monthly rents: $2200/ each unit = $4400/month.

Property B (side by side duplex) valued at $600,000 with 20% equity (owe $480K) on a 30 year fixed 3.5% int rate. - PITI: $3100/ month. We currently live in one unit and the other rents for $2300. Our owner occ. unit would rent for the same when we (ideally) move out after buying a single family. Total (future) rents =$4600/ month.

The issue is that the lendor I spoke with told me our DTI is too high to qualify for a conventional 30 yr. mortgage on a SF (approx $450K budget) approximate PITI: $3500/month

Our combined W2 wages are $145K/ year or $12K/month 

Total monthly debts: $450 (car pmt) + $180 (student loan) + $370 (fixed rate/term heloc on Property A) = $1000/month

Credit scores are: 780-800

Considering the debt services on the duplexs are completely covered and then some by 75% of the rental income I don't understand how we wouldn't qualify for financing a single family to use as a personal residence due to DTI. We would prefer not to refi/restructure the financing on the duplexs as we have great rates and doing so would put us in a less favorable financial position.

How do we move forward to get a mortgage on a single family? 

Any insight or help is greatly appreciated!