Split Duty hotac......
I'm also ex BCal and BA.
Split duty did have collateral cost saving spin off.......no slip crew; less deadheading and positioning; fewer overheads etc..
Usually only two rooms per crew in my experience.....male/female.
To be fair, benifit is more relaxation than sleep.
In BCal, mostly shorthaul, e.g. Europe.
In BA, longhaul internal shuttles, e.g. Oz, Japan, South Africa.