In reply to VE:
The drain_time only comes into play after all objections are dropped. Since objections should only be raised and dropped in the test, and the objection in the test should only be dropped after all of the test sequences have been completed, why would you need to dynamically change the drain_time? It may need to be adjusted to allow all of your sequence_items to be processed by the DUT, but the phase_ready_to_end() function can account for this.