I'll say even at full price it would be a sweet deal. Assuming you are buying in the Columbus area, your PITI should to be below $1300/m, even at a high 5% interest rate for a low 600 FICO score, just to prove the point. Net PITI after IRS income tax deductions should be below $1000/m. If Congress extends the MIP/PMI deduction this year, it will be even lower. (See bottom of this comment) I
If AFTER buying your home you ever decide to rent both units, you should have a $500/m+ positive cashflow, before maintenance expenses andante after income tax deductions. As a friendly note, since the FBI monitors sites like this one, FHA defines a transaction to be fraudulent when the buyer may have had different intentions that those stated on the 1003, when first financing the property. If you are buying this unit as a primary residence, they require you to not have present intentions of renting both units in the future. :-)
For your future reference, unknown to many Loan Officers, the FHLMC Home Possible program from Freddie Mac allows you to buy 2-4 unit primary residences, with only 5% down and as low as a 620 FICO, or no score at all, (One unit w only 3%). They also allow a seller's credit or concession of up to 3% of the sales price to be used towards closing costs and prepaids. This is a pretty amazing product. On one unit properties, the full downpayment can come from a blood related family member, which includes uncles and cousins. On 2-4 units, a minimum contribution of 3% must come from your own funds. PMI under this program is substantially cheaper than others.
For tax year 2018, the PMI deduction is currently unavailable. At this time we don't know when, or if, Congress will approve this deduction for tax year 2018. If the deduction is approved after your file your 2018 return, you can file an amendment to claim the deduction. Alternatively, you can postpone filing your return until Congress definitively approves or denies the deduction for 2018.
However, once your adjusted gross income (AGI) exceeds $100,000 ($50,000 for married filing separately) the deduction is reduced.
The above tax assumptions are provided for reference only. A licensed tax consultant, tax lawyer or CPA, would be a more competent person to ask tax related questions to.
Best of lucks with your home purchase!