Lender saying ADU/in law suite cant help me qualify for FHA Loan

[Nick H.]

Hey BP, I am in a bit of a bind trying to pencil out my second deal.

I am trying to buy a new construction side by side duplex. both units are identical to one another however for whatever reason it is not a legal two unit and is qualified as a single family home with a in law apt/ ADU.

Because of this my lender is unable to use the $16,800 gross revenue that half of the duplex is producing each year in order to help me qualify for the loan.

I don't understand two things,

1. The house is a side by side duplex. both units are identical and both have separate entrances, separate meters, why wouldn't this be a legal 2 unit?

2. even if it cant be considered a legal two unit, why cant my lender use the income that's already there? The tenants are on a lease. 

I'm really hoping to make this deal work, the numbers are real tight with my DTI and stuff so I need to be able to use the rental income.