[Kenwood] TS-850S ALC meter question

[W4WLC]

 I have a TS-850S that I bought used several months ago.  I have a question
about the ALC meter reading.  If I have the output power wide open and talk
into the mic and set the mic gain for a certain ALC meter reading it will
change as I am talking(usually drop lower).  The meter will drop down over
time while talking and I can re-adjust the mic gain to get where I had it. 
If you reduce the power after setting the mic gain say a full power and drop
the power back to half power the ALC meter reading will be way high.  The
people on the other end of the QSO do not notice any audio changes.  Is this
just the way this rig works or do I have a problem.  My 756 Pro II doesn't
do this, set the mic gain and you are good no matter what the power is set
at.
 
Thanks,
Dave
W4WLC