Did you literally say R - C, FC, VC, and Volume segment?
If so, the first mistake was not making it tailored to the case.
Secondly, remember that, always, you are solving a specific/tailored question. Your framework needs to have a clear objective and flow and set of hypotheses!
So, within FC and VC, what do you think they are? How do you think they're behaving? How would you go about determining what matters and what doesn't? For volume segments, are you splitting by product, customer, geography, etc. and why? How will you parse through the information for an answer.
By 2-3 layers they really likely mean you're missing the why and the how. A framework is a project plan, not a laundry list of items/ideas.
Hope this helps, and I highly recommend coaching to help instill this mindset shift!
General Framework Guide
If there's anything to remember in this process, is that cases don't exist just because. They have come about because of a real need to simulate the world you will be in when you are hopefully hired. As such, remember that they are a simplified version of what we do, and they test you in those areas.
As such, remember that a framework is a guide, not a mandate. In the real-world, we do not go into a client and say "right, we have a framework that says we need to look at x, y, and z and that's exactly what we're going to do". Rather, we come in with a view, a hypothesis, a plan of attack. The moment this view is created, it's wrong! Same with your framework. The point is that it gives us and you a starting point. We can say "right, part 1 of framework is around this. Let's dig around and see if it helps us get to the answer". If it does, great, we go further (but specific elements of it will certainly be wrong). If it doesn't, we move on.
So, in summary, learn your frameworks, use the ones you like, add/remove to them if the specific case calls for it, and always be prepared to be wrong. Focus rather on having a view, refering back to the initial view to see what is still there and where you need to dive into next to solve the problem.
Some other Q&As on Profitability for your reference