The interview consisted of two phases. The first one was with the person that I was replacing, as she was moving onto another project. I suspect that if you are applying for a new role, and not replacing someone, this part of the interview is conducted by the direct supervisor of the position. The second part is executed with the higher up bosses. They usually oversee more than one project, so the questions are not as specific as the ones in the first part. They are checking more general, organized and possibly wider knowledge of the branch you are applying for and the type of work that you will potentially be doing.