It's just the green up rule that needs arming multiple times, each time it triggers it will cancel any unmatched bets (inc, the previous green up order) so by the time the the new order arrives in the market the previous one will be gone.
There might be a rare time when your bets starts to get matched just as it triggers another green up order, in which case when this new bet arrives if it gets matched it will open a new position, but providing the rule still has triggers remaining it will then fire again and hopefully that one will green you up