This sounds like a worryingly familiar senario. I wonder how those who inititally pitched the ideas of serior phase would comment on this idea of bi and tri level teaching being used as it is today? Efficiencies at the cost of results.
I had success with N4/N5 bi level last year, the overlap in courses is such that it works well, this year Higher and Advanced higher not so much, there is too much content to teach both groups properly and get through it all in the time we had. To add further compromise they gave me 3 pupils crashing onto higher without programming experience at Nat5 level which mean more adjustment and less time for me to spread myself about.
Ive pushed back against this sort of course planning, it needs to have a teachers buy in to work and they need confidence in planning it before its agreed, it needs to have understanding about what curriculum overlap there is to find out if its even feasable, IMO there is too wide a gap for Nat5/Higher and Higher/Adv higher.
With only 1 Adv Higher candidate I can expect at least one nightmare but I suspect they will try and give me Nat4/Nat5/Higher this year and my hope is that they dont place the Adv Higher in that group otherwise I will get a quad level group!!!