After checking out several books and searching online, I have not, for the life of me, found answers to the following:
(1) Do form-based codes regulate density? I was under the impression that it only regulates form in different transects, and that inherently regulates density. But I am looking a the SmartCode, and it has something called "Base Residential Density", with units/acre, and it does not really explain what that means.
(2) If form-based codes regulate density, how can people gradually change density above or below their regulations? This question applies to form overall as well, which I suppose brings the whole idea of form-based codes into question. I am under the assumption that traditionally (as in before modern zoning began about 100 years ago in the US), densities and form changed gradually and organically, without having to change any regulations or designations for areas, like zones or transects or districts. If there is a desire or pressure to increase or reduce density above or below a numeric or form-based limit, or adapt form, I assume one would have to revise the designation for the area? If that is the case, making changes can be difficult and induce conflict that wouldn't have existed without the designation, and people would have accepted incremental changes. Thus, wouldn't any explicit or implicit density and form limitations severely restrict the ability for a place to change?