In using tags and creating searches based on tags - I have run into some issues.

Tag Tree Example

    Tag Set 1
         Parent A
              Child A1
                 Child A1a
                 Child A1b
                     Child A1ba
                     Child A1bb 
                 Child A1c 
              Child A2
          Parent B
              Child B1
                 Child B1a
                 Child B1b
                 Child B1c

In the above example - when I search for anyone tagged Parent A, I get every contact tagged Parent A and I get every contact tagged with any of the Children of Parent A.  This is what we want, so its great.  However, if I do a search for Child A1, I only get results for Child A1 and not the tags that Child A1 is the parent of.

Is this the correct behavior?  Can we change it?