SAIC interview questions

I received an email confirmation of my application on January 16th and received a phone call from a recruiter on February 6th. The recruiter asked me two questions. 1) Can you come down to Houston for an in person interview?, and 2) This position pays X dollars per year, are you okay with that? I replied "yes" to both questions. Afterwards, the recruiter told me that they'd call again to schedule an interview. I called the recruiter back on February 12th because I didn't hear back. They clarified that the interview would be over the phone for applicants living outside of the Houston area and that they'd call back to schedule a phone interview. They called back on February 18th and offered two interview times, 1) The morning of the 19th, or 2) The afternoon on the 20th. They also told me the name of the hiring manager I'd be speaking with. I went with the morning phone interview. The hiring manager called promptly at the scheduled time and the interview went pretty well, but I didn't expect there to be another interviewer with her. After the interview, the manager asked me if I could come down for an in person interview. I wanted to schedule another interview right then and there but it didn't seem like they were shooting for that. I was expecting a phone call, but was surprised with an email the next week with an employment offer.