Hi icyparadise,
I just checked with my friend, she said can apply right after 1st time failure. But she applied one year later due to personal reasons (not due to have to wait 6 months). Her case is several years ago, not sure about the situation now. But I have read someone's post in this forum said being called up for interview right after the previous round failure. So there's still hope for next round. Don't give up!
The policy may differ from time to time. It may also depends on the demand/vacancies. I think it's no harm just to submit another time in next round, if not being called up for interview, then try again next round.
All the best!