Properly Valuing a House After Repair

[O'Neil Mbakwe]

Good morning BP community! I'm having some issues properly comping a SFR I came across. The home is originally 2br /2bth , but the garage was converted to a bedroom, making it a 3br/2bth. The conversion renovation was subpar so I'd like to comp it as a 2br/2bth home. The problem I have is that all the homes in the neighborhood are 3/2 with a garage.

Is there a certain formula/deduction you would use to comp a 2/2 with a garage in a neighborhood full of 3/2 with a garage? Thanks.