I think that means more PWP. I think the minimum you need for a perfect town is 10-15 "good" PWP, not including Main St buildings. I think the "bad" ones are: picnic blanket, garbage can, and drilling rig.
EDIT: The PWP don't have to necessarily be different PWP. You can make 10 of the cheapest PWP and it will count as 10 separate PWP towards the perfect score.