Rent Roll - Underwriting Question

[Rick M.]

Hello,

I have been looking at T-12, rent rolls, etc for various properties for multifamily. One thing I did not understand on rent rolls in general is that there are unit types that are the same (same square ft), but charge separate rents (i.e. ranging from delta of $50-200 sometimes). I understand some are slightly better upgraded units that are noted which I understand, but sometimes they are $10-30 apart for the same unit). My question comes from underwriting purely. 

How do you classify it when you are underwriting a deal (meaning gross potential rents and subtracting the loss to leases and such)? I would think it would be cumbersome to list 5 Units A1 - $600, 6 Units - A1 - $610, 1 Unit A1 - $615 etc for each line item. Is there a more efficient way to go about it. 

I realize we have a T-12 and such, but when looking at the rent roll, I feel it does not make sense. Any advice? Thank you.