Is there an official mention of the activity cooling times for all the ranks here? Is it also related to activity?
Again in cases like that of OP it should get automatically reduced on achieving a good number of valid reports.
Like mdayonliner said, this time is shared between every "activity" you do. Reporting, posting, login in, meriting, PMing, etc...
And this is the formula for the limit:
waittime = 360;
if(activity >= 15)
waittime = (int)(90 - activity);
if(activity >= 60)
waittime=(int)(34.7586 - (0.0793103 * activity));
if(activity >= 100)
waittime = max((int)(14-(activity/50)), 4);