Thanks for the clarification -- that's what I suspected, but thought I must be misreading or misunderstanding, but I also don't know your situation and trust you're making the right set of trade-offs here. If your system is today a cuttlefish, yesterday a cow, and tomorrow a crab, cow tests don't do you much good. That sounds like a crazy environment, and I'd maybe have a care that those hapless idiots are sane people in an insane place.

You sound like you're in that category if you can't differentiate and think that it's surprising for software to have a flexible business logic layer.