FDXMECH and COMXTECH,
It is not entirely clear what type of systems you are both describing. Nor indeed whether you are describing the same aircraft type.
COMXTECH, You appear to be talking about what in JAR speak is internal balance, but you also refer to balance tabs.
FDXMECH, You appear to be talking about a type of servo tab system which becomes operational only in manual control mode. Most JAR ATPL training manuals discuss only the type of servo tab that is used in un-powered control systems.
Which aircraft are you decsribing and what exactly do they employ?
This is a matter of some significance to JAR ATPL students in that it may give a better insight into what exactly the examiners are looking for in this question.