Unfortunately, it seems like August SAT seats have been fully booked for a while for most locations. I think you’re actually pretty lucky that there are 2 seats within 50 miles, and I would probably take it if it is at all possible. August is the prime time.
I would also consider registering for the October test soon, if money is not an issue. It will be a really tight window, and will only be available for Nov 1 deadlines, but at least there’s a tiny window there.