Buying a Quadplex in Las Vegas - Newb Question

[Steven Walford]

We recently sold our first rental and are now trying to use proceeds to get multiple units and diversify. I have found a quadplex in Las Vegas that is 2x2 per unit (bed and bath). Each unit is currently filled and upon purchase each renter would sign a new 1 year lease. After doing some financials (waiting to hear back from our lender) I think the profit will be lower then anticipated. I was hoping that 3 units would cover the costs of the property/loan and the 4th unit would be profit. Should I focus on set profit margin or focus on the property just covering its own costs??? Not trying to get rich quick but we would like to be able to use the profits on the unit to pay down the loan but is it reasonable to expect the 4th unit to be all profit? Which What I have down on paper the 4th unit would only profit 50%.

Thanks in advance