In addition the delaying rule only applies at the end of the round.
In battle the timer is there to force the two teams into conflict quickly, only when a battle is glitched does the timer run itself all the way down. So the end of the round in regular battle is when one team has all but been eliminated save a few people avoiding conflict to leech multipliers, or because they are cowards.
In strat the entire point, if defending, is usually to fight until the timer runs out and then drive the attackers off. There is quite a bit that can go on after the timer runs down. Therefor the end of the round is not until the timer has completely run out, so any defensive tactics before that ought to be allowed.