When I sold new developments Friday off made sense. Weekends are the busiest days, and the days after would be needed to follow up, dealing with contracts written on the weekend etc.
Things would tale off towards the end of the week, so Friday made the most sense to close if a day is needed for closing.
Lots of developments have 1-2 sales people only, so having 1 day off seems reasonable to me, and they've picked the most logical day.