Upsher-Smith interview questions

After passing the hiring manager, then scheduled 4 interviews. And two of them were just asking similar questions to previous, I do not understand why the structure of interview is like this. Changed interview like around 3 times, last interviewer said I only have 20 min because of conflict. I scheduled a week ago, and this is the one of interview that changed time by the way.

Full onsite interview including a technical presentation, multiple one to one interviews, and also a group lunch, facility tour. Lasted one full day. The facility tour is quite useful and interactive.