Internally balanced engines are completely balanced by the crankshaft, their external components (dampener, flex/flywheel) are neutral balanced (zero imbalance). In comparison, externally balanced engines require the use of matched imbalanced external parts in order to bring the entire rotating assembly into neutral balance once assembled. That is why you must use matched components, they are counting on each other to be a certain imbalance, for SBF: 50oz or 28oz. By saying you have a 28oz internal balanced flex/flywheel is kinda weird. Any internally balanced engine's external components would be zero imbalance. Make sense?
