ORIGINAL: Rodney
Unless someone is redefining the definitions of ''balance'' and ''boost'' there is no similarity between the two. Balance meaning to have equal force about a pivot point, boost being an augment to the applied force. In fact, most boost tabs will be counteracting to balance as they usually contribute more static unbalance to the assembly as they are adding mass aft of the hinge or pivot point. There is also a difference between static and aerodynamic balance and either one or both can be accomplished with different implementation of structure. For instance, static and aerodynamic balance can be obtained by properly weighting the area ahead of the hinge line where that type of balance is implemented.
Rodney,
Aerodynamic 'balance' and mass 'balance' are two different things.
In aerodynamics, control 'balance' refers to the force required to move the control surface and how that force varies with speed, deflection, and G force (there's more). We are discussing tabs that affect this balance hence balance tabs. I agree thats not quite the same as balance about a pivot (see saw or teeter totter?) balance
Mass 'balance' is about balancing the control surface about the hinge ie pivot line. This is mostly done to prevent flutter.
Confusion can arise because a common method of aerodynamic balancing, the horn balance (eg the top of a cub rudder), is often used as a good place to install the mass balance weight. The mass is there to prevent or reduce flutter, the horn is there to reduce the control force.
You can't change the aerodynamic balance with weight.
Dave H