"When interviewing for an account owner position, be prepared to speak to your skills in communications, marketing, and client relations. Employers will be interested in your ability to create long lasting relationships with clients and generate sales for a portfolio of accounts. Your interviewer may test your abilities with a role play question, so be prepared to give a mock sales pitch to a difficult client."
most unexpected was they give you a benchmark report, which is a product they produce for clients... and then ask you questions about it to see if you have a feeling for figures
you'll be fine if you are not a complete idiot with maths