My wife got the same situation, She came to USA at F2 and changed to F1 in USA, she graduated last year and she didn't find a job during her OPT. and then She went back to china this Auguest and got her H4 visa in Beijing this month without any trouble.
the questions which VO ask:
1) how many times you enter USA?
answer: 4times
2)why you came back from USA?
answer: took my son to see grandparents
3)do you still bring your son back?
answer: yes.
4) do you know H4 visa holder have no permission to work in USA?
answer: Yes, I do.