Edited 3/22/2019 to soften my conclusions about Sunrise and 100 beds. Edited late 3/22/2019 to explain what all those eight-bed assisted living facilities are.
On this page, I assemble, map, and tabulate some fairly hard-to-find data on a) location of all licensed assisted living facilities in Fairfax County, and b) the base monthly rates charged by most of them (2017 data).
Surprisingly, the table of monthly rates goes a long way toward explaining Sunrise’s behavior at the last Planning Commission meeting. When questioned about five floors in their building, they were prepared. They whipped out several other sets of building plans, all of which had more-or-less the same number of beds as their original plan. And now I see that the Sunrise buildings in Fairfax (or, at least, for which I could find monthly price data) mostly cluster tightly between 100 and 120 beds. It looks like they build these for a standard operating model. So, one way or the other, I would guess, they’re going to get their 100 beds.