I had FOUR interviews: the first three were technical and had INCREASED in difficulty. The fourth interview was with a Sr. Collab. Mgr., which was all about being a great, cultural fit with the company or not. The interviews per telephone will be different regional gurus whom are at the top of their craft so if you don't get all of them right, then it's fine. Just answer eloquently and articulately as possible!!! If you do not know it, just don't dilly-dally; be upfront and forward.