When any post is reported, it creates a thread within the mods' forum. The timer for the amount of time between posts is a universal timer, being the same for all posts throughout the forum. A special timer cannot be set for reporting spam (or any other reporting).
The timer is currently set for 30 seconds. This time will not be reduced, and probably should be increased. It is there to prevent flooding of the forums by spammers and/or bots. Yes, it can be inconvenient at times, but it is there for a reason.