Does NYC have special rules regards SFR - 3 units vs 4 + units?

[Josh Louis]

I was talking to an agent in the Bronx and she said she doesn't really deal with 4+ units in the area because they aren't worth the inspection headache. Just to name a few of the issues,

• - full inspections by various organizations e.i. Fire marshal
• - strict pricing guidelines from brokers

I thought this only pertained to 5+ units as they are considered commercial and anything below that is residential and thus not subject to the same restrictions. 

Is this different in NYC?

Thanks