CSB Overtime Handler keeps its own copy of the round score by listening to the CT/T win radio events, so it does not depend on any external match system. When the number of rounds played reaches mp_maxrounds and the score is level, it starts an overtime: mp_maxrounds is extended by a full OT block (played on both sides), a fresh OT start money is set, and the round is restarted so the money and freeze apply cleanly. Overtimes repeat until one side finishes ahead.
csb_ot_rounds.csb_ot_money.csb_overtime_handler.sma and copy it to addons/amxmodx/plugins/.plugins.ini and change the map.