Agreed with respect to free ...

Agreed with respect to free chlorine pertaining to HOCl (and OCl- ion) in solution however it gets there.  Agreed also with respect to various chloramines, portraying combined chlorine species.  Total chlorine is the sum total of chloramines, free chlorine, and also any other free halogen in the system.  For example, I use a bromine release agent in cooling water due to selection of a higher pH program where free chlorine is not as effective.  The addition of this bromine results in a better kill at the higher pH, and also results in a "free chlorine" residual that would not normally be present given our source water being chloraminated.