it might not be flexible at all because their will be those who have been there years and will have a choice of hours and the op will get whatever ya get. he is entering a huge corporate company, op don't have a choice in anything..
Oh jeez, do you really think anybody here knows the particulars? I wouldn't worry about it until you at least have an interview, and then I would ask at said interview about how flexible they may be. It isn't rocket science.