To the original poster, this advise is too late, but why even bother justifying the five month absence from this country? It is possible USCIS checks records outside the country, but I am certain it probably does not happen much, if at all. Even then, they would likely check a criminal record and not good behavior like school attendance.

In this situation, I would have gambled by leaving it blank and hope I was approved without those months; Some people have with similar gaps. If not, I would have waited for an RFE or sent anything with my name during the time I was gone. Like letters my family would of received when I left . I call it a loophole... Not fraud x)