No, you bring up your findings in discovery, NOT LONG AFTER discovery and on the last day of "expert discovery." In discovery, you present your theories. In expert discovery, you present evidence to support those theories and refute the opposing party's theories. Defendants requested and agreed to present four theories. In discovery they presented four theories. Chanbond's expert discovery surrounded those four theories. On the last day of expert discovery, defendants introduced a new, fifth theory.
In poker, since your keen on gaming analogies, that would be akin to pulling an extra card out of your sleeve just as everyone is laying their cards on the table.