@eons: that's what i did

For those who want a more realistic number of households, you can use a mod like Realistic Population 2 to increase it. From sources I found online, the real-life apartment block has 75 4-room units and 75 5-room units (both are what other countries would term 3-bedroom apartments; the main difference here is that 5-room units have a study area attached to the living room), so 75+75=150 units or households.

First: You should add information like name, space require and level in order so it would look like then the detail about it.
Also about your "The number of households is pathetic at 6 households. I have no idea how to edit that in the asset editor as I do not see any settings for it. The game probably didn't recognise that this isn't just a small 2x2..."
The game only count the space it take horizontal instead of vertical so it doesn't regconize how many household is this building.
You could use those varient of mods that like Realistic Population mods.

sugoi

is it growable?

https://steamcommunity.com/sharedfiles/filedetails/?id=426163185

This mod will help you change the number of families of your buildings to a more realistic number :)

P.S. Your buildings look real nice ;)

Should be able to use RICO mod to change the numbers of occupants.

that's more beautiful than my 2nd wife

Looks cool, just wish every single apartment isn't on at night :p