Thank you very much for the explanation.  I uninstalled my previous versions of the 777-200 and the 777-4
300 and installed the .4 version of both and so far, the 777-300 is holding the authothrottle.  Very good.  Still have to test it on the 777-200, but assume it will work as that is the base pack for the 300 version.  Thank you very much for the turnaround for the fix on this.  One thing, however, and this is a small point, the 777-300 is holding at my designated altitude of 32000 feet, but the FMC is programmed for a mach speed of .833 and it is actually holding at .824.