I just talked to the company looking for the exp-600 that I paid for in July . They have admitted that they are not even production. They hope to start up in mid Oct. that means with there back log, it unlikely to see a unit until the end of the year. This is so unprofessional . Now , I don't know what I will do. If I could find an alternative that would work with my advanced 4500, I would do it. Any ideas?