Do not assume that the AP will end in a confirmed visa. The administrative process is part of their procedure to further investigation. Something must have been strange in your interview. Some document must not be standard.
e.g. the spelling of your name in some official documents gets fudged up because of underpaid gormint clerks writing in "insect language" like if you name has Muhammad in it and somewhere its written as Mohammad - its a suspicion call for them and into AP you go.
I know people who have been called again for interview. Mostly those people had some really odd situations like internal family marriages or some really oddball situations, like in your B1/B2 your current business or something related to it would not be adding up.. btw what are your plans on the B visa.
