I think the top deployments are those similar to a crossover.
Like BBDEP 166/170A* I see 6027K 6722L 6206K on their perm services
as well during off peak hours.
I believe their ads are shared between the two.
As for the bottom deployment to spare, yes they are running
around often.
6773P used to do 170A when it had an ad, after ad taken down, 6773P
dont do 170A anymore but 6206K like the only adless buses doing
170A consistently