Do all lenders count a basement living space as a 5th unit?

[Navin Francis]

I am looking at a 4 + 1 unit in the basement property in Steger, IL. Trying to get lender to approve this as a 4 unit to take advantage of the conventional residential loan, however the lender counts the basement as a unit and that makes this a 5 unit commercial loan scenario. The current owner was able to get a residential loan on this property previously. The village considers this a non-conforming legal multi-unit without mention of number of units. 

Is there anyway I can satisfy the lender to approve this as a 4 unit with basement for a residential conventional loan?