I had my interview at the Dallas DO today May 14th. It went very well. I was very nervous about my extensive travel over the past 5 years. I had some 800 odd days of travel that included trips to a lot of countries in the world. But none of my trips was over 6 months, the maximum trip length was 110 days. I was working for a US company as a contractor and did have a letter from the company for the reason for the numerous visits.
Recently USCIS erroneously scheduled some customers for more than one Application Support Center (ASC) biometric appointment (Form I-797C).
If you have already attended an ASC biometric appointment, and received a second appointment notice for the same application type, please call the National Customer Service Center at 1-800-375-5283 (TTY for hearing impaired: 1-800-767-1833) to confirm that you do not need to return to the ASC to have biometrics collected again.