Hi there,
I believe there is a bit of confusion in your definition of interviewer vs interviewee-led cases.
You will still have to present a structure and formulate hypotheses in interviewer-led cases. The difference is that the interviewer will not let you continue on your own after you presented, but ask specific questions on a particular section of the problem, whether you have presented it or not.
If you are good with an interviewee-led case you won’t have issues with an interviewer-led one - just be aware the interviewer may stop you while you are presenting and ask you to move to the next topic.
On the other hand, people familiar with interviewer-led cases may find interviewee-led ones more challenging, as they are not used to drive the case. This is common negative feedback that candidates who prepared solely with an interviewer-led approach get at BCG and Bain.
To sum up: get used to the interviewee-led approach when you prepare for cases. The interviewer-led flow will then be easy to follow if the case has that format. If you see the interviewer wants to lead the case and bring you to a specific section – just follow his/her direction and you will be fine.
Best,
Francesco